Before changing the DHCP server mode to the DHCP relay agent mode on an interface, use the reset dhcp server ip-in-use command to remove address bindings and authorized ARP entries. These bindings might conflict with ARP entries that are created after the DHCP relay agent is enabled.

Examples

# Enable the DHCP relay agent on VLAN-interface 2.

<Sysname> system-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] dhcp select relay

Related commands

reset dhcp server ip-in-use

DHCP server commands

The DHCP server configuration is supported only on Layer 3 Ethernet interfaces (or subinterfaces), VLAN interfaces, Layer 3 aggregate interfaces, and loopback interfaces.

address range

Use address range to configure an IP address range in a DHCP address pool for dynamic allocation.

Use undo address range to remove the IP address range in the address pool.

Syntax

address range start-address end-address

undo address range

Default

No IP address range is configured.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

start-address: Specifies the start IP address.

end-address: Specifies the end IP address.

Usage guidelines

If no IP address range is specified, all IP addresses in the subnet specified by the network command in address pool view are assignable. If an IP address range is specified, only the IP addresses in the IP address range are assignable.

After you use the address range command, you cannot use the network secondary command to specify a secondary subnet in the address pool.

If you use the command multiple times, the most recent configuration takes effect.

The address range specified by the address range command must be within the subnet specified by the network command, and the addresses out of the address range cannot be assigned.

Examples

# Specify an address range of 192.168.8.1 through 192.168.8.150 in address pool 1.

<Sysname> system-view

[Sysname] dhcp server ip-pool 1

[Sysname-dhcp-pool-1] address range 192.168.8.1 192.168.8.150

Related commands

· class

· dhcp class

· display dhcp server pool

· network

bims-server

Use bims-server to specify the IP address, port number, and shared key of the BIMS server in a DHCP address pool.

Use undo bims-server to remove the specified BIMS server information.

Syntax

bims-server ip ip-address [ port port-number ] sharekey { cipher | simple } key

undo bims-server

Default

No BIMS server information is specified.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

ip ip-address: Specifies the IP address of the BIMS server.

port port-number: Specifies the port number of the BIMS server, in the range of 1 to 65534.

cipher: Sets a ciphertext key.

simple: Sets a plaintext key.

key: Specifies the key string. This argument is case sensitive. If simple is specified, it must be a string of 1 to 16 characters. If cipher is specified, it must be a ciphertext string of 1 to 53 characters. The DHCP client uses the shared key to encrypt packets sent to the BIMS server.

Usage guidelines

If you use this command multiple times, the most recent configuration takes effect.

For secrecy, all passwords, including passwords configured in plaintext, are saved in ciphertext.

Examples

# Specify the BIMS server IP address 1.1.1.1, port number 80 and shared key aabbcc in address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] bims-server ip 1.1.1.1 port 80 sharekey simple aabbcc

Related commands

display dhcp server pool

bootfile-name

Use bootfile-name to specify a boot file name in a DHCP address pool.

Use undo bootfile-name to remove the specified boot file name.

Syntax

bootfile-name bootfile-name

undo bootfile-name

Default

No bootfile name is specified.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

bootfile-name: Specifies the boot file name, a case-sensitive string of 1 to 63 characters.

Usage guidelines

If you use the bootfile-name command multiple times, the most recent configuration takes effect.

Examples

# Specify the boot file name boot.cfg in DHCP address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] bootfile-name boot.cfg

Related commands

· display dhcp server pool

· next-server

· tftp-server domain-name

· tftp-server ip-address

class

Use class to specify an IP address range for a DHCP user class.

Use undo class to remove the IP address range for the DHCP user class.

Syntax

class class-name range start-address end-address

undo class class-name

Default

No IP address range is specified for a DHCP user class.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

class-name: Specifies the name of a DHCP user class, a case-insensitive string of 1 to 63 characters. If the specified user class does not exist, the DHCP server will not assign the addresses in the address range specified for the user class to any client.

start-address: Specifies the start IP address.

end-address: Specifies the end IP address.

Usage guidelines

The class command enables you to divide an address range into multiple address ranges for different DHCP user classes. The address range for a user class must be within the primary subnet specified by the network command. If the DHCP client does not match any DHCP user class, the DHCP server selects an address in the IP address range specified by the address range command. If the address range has no assignable IP addresses or no address range is configured, the address allocation fails.

You can specify only one address range for a DHCP user class in an address pool. If you use the class command multiple times for a DHCP user class, the most recent configuration takes effect.

After you specify an address range for a user class, you cannot use the network secondary command to specify a secondary subnet in the address pool.

Examples

# Specify an IP address range of 192.168.8.1 through 192.168.8.150 for the DHCP user class user in DHCP address pool 1.

<Sysname> system-view

[Sysname] dhcp server ip-pool 1

[Sysname-dhcp-pool-1] class user range 192.168.8.1 192.168.8.150

Related commands

· address range

· dhcp class

· display dhcp server pool

dhcp class

Use dhcp class to create a DHCP user class and enter the DHCP user class view. If the user class has already been created, you directly enter the user class view.

Use undo dhcp class to remove the specified user class.

Syntax

dhcp class class-name

undo dhcp class class-name

Default

No DHCP user class exists.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

class-name: Specifies the name of a DHCP user class, a case-insensitive string of 1 to 63 characters.

Usage guidelines

In the DHCP user class view, use the if-match option command to configure a match rule to match specific clients. Then use the class command to specify an IP address range for the matching clients.

Examples

# Create a DHCP user class test and enter DHCP user class view.

<Sysname> system-view

[Sysname] dhcp class test

[Sysname-dhcp-class-test]

Related commands

· address range

· class

· if-match option

dhcp server always-broadcast

Use dhcp server always-broadcast to enable the DHCP server to broadcast all responses.

Use undo dhcp server always-broadcast to restore the default.

Syntax

dhcp server always-broadcast

undo dhcp server always-broadcast

Default

The DHCP server reads the broadcast flag in a DHCP request to decide whether to broadcast or unicast the response.

Views

System view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

This command enables the DHCP server to ignore the broadcast flag in DHCP requests and broadcast all responses.

Upon receiving a DHCP request from a DHCP relay agent (the giaddr field is not 0), the DHCP server unicasts a response (the destination address is giaddr) to the DHCP relay agent regardless of whether this command is executed.

Examples

# Enable the DHCP server to broadcast all responses.

<Sysname> system-view

[Sysname] dhcp server always-broadcast

dhcp server apply ip-pool

Use dhcp server apply ip-pool to apply an address pool on an interface.

Use undo dhcp server apply ip-pool to remove the configuration.

Syntax

dhcp server apply ip-pool pool-name

undo dhcp server apply ip-pool

Default

No address pool is applied on an interface

Views

Interface view

Predefined user roles

network-admin

mdc-admin

Parameters

pool-name: Specifies the name of a DHCP address pool, a case-insensitive string of 1 to 63 characters.

Usage guidelines

Upon receiving a DHCP request from the interface, the DHCP server searches for a static binding for the client from all address pools. If no static binding is found, the server assigns configuration parameters from the address pool applied on the interface to the client. If the address pool has no assignable IP address or does not exist, the DHCP client cannot obtain an IP address.

If you use the command multiple times, the most recent configuration takes effect.

Examples

# Apply DHCP address pool 0 on VLAN-interface 2.

<Sysname> system-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] dhcp server apply ip-pool 0

Related commands

dhcp server ip-pool

dhcp server bootp ignore

Use dhcp server bootp ignore to configure the DHCP server to ignore BOOTP requests.

Use undo dhcp server bootp ignore to restore the default.

Syntax

dhcp server bootp ignore

undo dhcp server bootp ignore

Default

The DHCP server does not ignore BOOTP requests.

Views

System view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

The lease duration of IP addresses obtained by BOOTP clients is unlimited. For scenarios that do not allow unlimited leases, you can configure the DHCP server to ignore BOOTP requests.

Examples

# Configure the DHCP server to ignore BOOTP requests.

<Sysname> system-view

[Sysname] dhcp server bootp ignore

dhcp server bootp reply-rfc-1048

Use dhcp server bootp reply-rfc-1048 to enable the DHCP server to send BOOTP responses in RFC 1048 format upon receiving BOOTP requests incompliant with RFC 1048.

Use undo dhcp server bootp reply-rfc-1048 to disable this function.

Syntax

dhcp server bootp reply-rfc-1048

undo dhcp server bootp reply-rfc-1048

Default

This function is disabled. The DHCP server does not process the Vend field of such packets but directly copies the field into the responses.

Views

System view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

This command enables the DHCP server to fill in the Vend field using the RFC 1048-compliant format in DHCP responses to RFC 1048-incompliant requests sent by BOOTP clients.

This command takes effect only for BOOTP clients that request for a statically bound address.

Examples

# Enable the DHCP server to send BOOTP responses in RFC 1048 format upon receiving BOOTP requests incompliant with RFC 1048.

<Sysname> system-view

[Sysname] dhcp server bootp reply-rfc-1048

dhcp server forbidden-ip

Use dhcp server forbidden-ip to exclude specific IP addresses from dynamic allocation.

Use undo dhcp server forbidden-ip to remove the configuration.

Syntax

dhcp server forbidden-ip start-ip-address [ end-ip-address ]

undo dhcp server forbidden-ip start-ip-address [ end-ip-address ]

Default

No IP addresses are excluded from dynamic allocation.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

start-ip-address: Specifies the start IP address.

end-ip-address: Specifies the end IP address, which cannot be lower than the start-ip-address. If you do not specify the argument, only the start-ip-address is excluded from dynamic allocation. If you specify the argument, the IP addresses from start-ip-address through end-ip-address are all excluded from dynamic allocation.

Usage guidelines

The IP addresses of some devices such as the gateway and FTP server cannot be assigned to clients. Use this command to exclude such addresses from dynamic allocation.

You can exclude multiple IP address ranges from dynamic allocation.

If the excluded IP address is in a static binding, the address can be still assigned to the client.

The address or address range specified in the undo form of the command must be the same as the address or address range specified in the command. To remove an IP address that has been specified as part of an address range, you must remove the entire address range.

Examples

# Exclude the IP addresses of 10.110.1.1 through 10.110.1.63 from dynamic allocation.

<Sysname> system-view

[Sysname] dhcp server forbidden-ip 10.110.1.1 10.110.1.63

Related commands

· forbidden-ip

· static-bind

dhcp server ip-pool

Use dhcp server ip-pool to create a DHCP address pool and enter its view. If the pool has been created, you directly enter its view.

Use undo dhcp server ip-pool to remove the specified DHCP address pool.

Syntax

dhcp server ip-pool pool-name

undo dhcp server ip-pool pool-name

Default

No DHCP address pool is created.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

pool-name: Specifies the name for the DHCP address pool, a case-insensitive string of 1 to 63 characters used to uniquely identify this pool.

Usage guidelines

A DHCP address pool is used to store the configuration parameters to be assigned to DHCP clients.

Examples

# Create a DHCP address pool named pool1.

<Sysname> system-view

[Sysname] dhcp server ip-pool pool1

[Sysname-dhcp-pool-pool1]

Related commands

· dhcp server apply ip-pool

· display dhcp server pool

dhcp server ping packets

Use dhcp server ping packets to specify the maximum number of ping packets.

Use undo dhcp server ping packets to restore the default.

Syntax

dhcp server ping packets number

undo dhcp server ping packets

Default

The maximum number of ping packets is 1.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

number: Specifies the maximum number of ping packets, in the range of 0 to 10. A value of 0 indicates that the DHCP server does not perform address conflict detection.

Usage guidelines

To avoid IP address conflicts, the DHCP server pings an IP address before assigning it to a DHCP client.

If a ping attempt succeeds, the server considers that the IP address is in use and picks a new IP address. If all the ping attempts are failed, the server assigns the IP address to the requesting DHCP client.

Examples

# Specify the maximum number of ping packets as 10.

<Sysname> system-view

[Sysname] dhcp server ping packets 10

Related commands

· dhcp server ping timeout

· display dhcp server conflict

· reset dhcp server conflict

dhcp server ping timeout

Use dhcp server ping timeout to configure the ping response timeout time on the DHCP server.

Use undo dhcp server ping timeout to restore the default.

Syntax

dhcp server ping timeout milliseconds

undo dhcp server ping timeout

Default

The ping response timeout time is 500 ms.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

milliseconds: Specifies the timeout time in the range of 0 to 10000 milliseconds. To disable the ping operation for address conflict detection, set the value to 0 milliseconds.

Usage guidelines

To avoid IP address conflicts, the DHCP server pings an IP address before assigning it to a DHCP client.

Examples

# Specify the response timeout time as 1000 ms.

<Sysname> system-view

[Sysname] dhcp server ping timeout 1000

Related commands

· dhcp server ping packets

· display dhcp server conflict

· reset dhcp server conflict

dhcp server relay information enable

Use dhcp server relay information enable to enable the DHCP server to handle Option 82.

Use undo dhcp server relay information enable to configure the DHCP server to ignore Option 82.

Syntax

dhcp server relay information enable

undo dhcp server relay information enable

Default

The DHCP server handles Option 82.

Views

System view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

Upon receiving a DHCP request containing Option 82, the server copies the original Option 82 into the response. If the server is configured to ignore Option 82, the response will not contain Option 82.

Examples

# Configure the DHCP server to ignore Option 82.

<Sysname> system-view

[Sysname] undo dhcp server relay information enable

display dhcp server conflict

Use display dhcp server conflict to display information about IP address conflicts.

Syntax

display dhcp server conflict [ ip ip-address ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

ip ip-address: Displays the conflict information for the specified IP address. If no IP address is specified, this command displays information about all IP address conflicts.

Usage guidelines

The DHCP server creates IP address conflict information in the following conditions:

· Before assigning an IP address to a DHCP client, the DHCP server pings the IP address and discovers that it has been used by other host.

· The DHCP client sends a DECLINE packet to the DHCP server to inform the server of an IP address conflict.

· The DHCP server discovers that the only assignable address in the address pool is its own IP address.

Examples

# Display information about all IP address conflicts.

<Sysname> display dhcp server conflict

IP address Detect time

4.4.4.1 Apr 25 16:57:20 2007

4.4.4.2 Apr 25 17:00:10 2007

Table 1 Command output

Field	Description
IP address	Conflicted IP address.
Detect time	Time when the conflict was discovered.

Related commands

reset dhcp server conflict

display dhcp server expired

Use display dhcp server expired to display the lease expiration information.

Syntax

display dhcp server expired [ ip ip-address | pool pool-name ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

ip ip-address: Displays the lease expiration information for the specified IP address.

pool pool-name: Displays the lease expiration information for the specified address pool. The pool name is a case-insensitive string of 1 to 63 characters.

Usage guidelines

If you do not specify any parameter, this command displays the lease expiration information for all address pools.

DHCP will assign these expired IP addresses to DHCP clients when all available addresses have been assigned.

Examples

# Display all lease expiration information.

<Sysname> display dhcp server expired

IP address Client-identifier/Hardware address Lease expiration

4.4.4.6 3030-3066-2e65-3230-302e-3130-3234 Apr 25 17:10:47 2007

-2d45-7468-6572-6e65-7430-2f31

Table 2 Command output

Field	Description
IP address	Expired IP address.
Client-identifier/Hardware address	Client ID or MAC address.
Lease expiration	Time when the lease expired.

Related commands

reset dhcp server expired

display dhcp server free-ip

Use display dhcp server free-ip to display information about assignable IP addresses.

Syntax

display dhcp server free-ip [ pool pool-name ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

pool pool-name: Displays assignable IP addresses in the specified address pool. The pool name is a case-insensitive string of 1 to 63 characters. If you do not specify any address pool, this command displays all assignable IP addresses for all address pools.

Examples

# Display assignable IP addresses in all address pools.

<Sysname> display dhcp server free-ip

Pool name: 1

Network: 10.0.0.0 mask 255.0.0.0

IP ranges from 10.0.0.10 to 10.0.0.100

IP ranges from 10.0.0.105 to 10.0.0.255

Secondary networks:

10.1.0.0 mask 255.255.0.0

IP ranges from 10.1.0.0 to 10.1.0.255

10.2.0.0 mask 255.255.0.0

IP Ranges from 10.2.0.0 to 10.2.0.255

Pool name: 2

Network: 20.1.1.0 mask 255.255.255.0

IP ranges from 20.1.1.0 to 20.1.1.255

Table 3 Command output

Field	Description
Pool name	Name of the address pool.
Network	Assignable network.
IP ranges	Assignable IP address range.
Secondary networks	Assignable secondary networks.

Related commands

· address range

· dhcp server ip-pool

· network

display dhcp server ip-in-use

Use display dhcp server ip-in-use to display the binding information for assigned IP addresses.

Syntax

display dhcp server ip-in-use [ ip ip-address | pool pool-name ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

ip ip-address: Displays binding information for the specified IP address.

pool pool-name: Displays binding information for the specified IP address pool. The pool name is a case-insensitive string of 1 to 63 characters.

Usage guidelines

If you do not specify any parameter, the command displays the binding information for all assigned DHCP addresses.

If the lease deadline exceeds the year 2100, the lease expiration time is displayed as After 2100.

Examples

# Display binding information for all assigned DHCP addresses.

<Sysname> display dhcp server ip-in-use

Pool utilization: 0.39%

IP address Client identifier/ Lease expiration Type

Hardware address

10.1.1.1 4444-4444-4444 Not used Static(F)

10.1.1.2 3030-3030-2e30-3030- May 1 14:02:49 2009 Auto(C)

662e-3030-3033-2d45-

7468-6572-6e65-7430-

2f31

10.1.1.3 1111-1111-1111 After 2100 Static(C)

Table 4 Command output

Field	Description
Pool utilization	Pool utilization rate: · If you display binding information for all address pools, this field displays the utilization rate of all address pools. · If you display binding information for an address pool, this field displays the pool utilization rate of the specified address pool. · If you display binding information for the specified IP address, this field is not displayed.
IP address	IP address assigned.
Client identifier/Hardware address	Client ID or hardware address.
Lease expiration	Lease expiration time: · Exact time (May 1 14:02:49 2009 in this example)—Time when the lease will expire. · Not used—The IP address of the static binding has not been assigned to the specific client. · Unlimited—Infinite lease expiration time. · After 2100—The lease will expire after 2100.
Type	Binding types: · Static(F)—A free static binding whose IP address has not been assigned. · Static(O)—An offered static binding whose IP address has been selected and sent by the DHCP server in a DHCP-OFFER packet to the client. Static(C)—A committed static binding whose IP address has been assigned to the DHCP client. · Auto(O)—An offered temporary dynamic binding whose IP address has been dynamically selected by the DHCP server and sent in a DHCP-OFFER packet to the DHCP client. · Auto(C)—A committed dynamic binding whose IP address has been dynamically assigned to the DHCP client.

Related commands

reset dhcp server ip-in-use

display dhcp server pool

Use display dhcp server pool to display information about a DHCP address pool.

Syntax

display dhcp server pool [ pool-name ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

pool-name: Displays information about the specified address pool. The pool name is a case-insensitive string of 1 to 63 characters. If you do not specify any pool-name, the command displays information about all address pools.

Examples

# Display information about all DHCP address pools.

<Sysname> display dhcp server pool

Pool name: 0

Network 20.1.1.0 mask 255.255.255.0

class a range 20.1.1.50 20.1.1.60

bootfile-name abc.cfg

dns-list 20.1.1.66 20.1.1.67 20.1.1.68

domain-name www.aabbcc.com

bims-server ip 192.168.0.51 sharekey 1

option 2 ip-address 1.1.1.1

expired 1 2 3 0

Pool name: 1

Network 20.1.1.0 mask 255.255.255.0

secondary networks:

20.1.2.0 mask 255.255.255.0

20.1.3.0 mask 255.255.255.0

bims-server ip 192.168.0.51 port 50 sharekey 1

forbidden-ip 20.1.1.22 20.1.1.36 20.1.1.37

forbidden-ip 20.1.1.22 20.1.1.23 20.1.1.24

gateway-list 1.1.1.1 2.2.2.2 4.4.4.4

nbns-list 5.5.5.5 6.6.6.6 7.7.7.7

netbios-type m-node

option 2 ip-address 1.1.1.1

expired 1 0 0 0

Pool name: 2

Network 20.1.1.0 mask 255.255.255.0

address range 20.1.1.1 to 20.1.1.15

class departmentA range 20.1.1.20 to 20.1.1.29

class departmentB range 20.1.1.30 to 20.1.1.40

next-server 20.1.1.33

tftp-server domain-name www.dian.org.cn

tftp-server ip-address 192.168.0.120

voice-config ncp-ip 10.1.1.2

voice-config as-ip 10.1.1.5

voice-config voice-vlan 3 enable

voice-config fail-over 10.1.1.1 123*

option 2 ip-address 1.1.1.3

expired 1 0 0 0

Pool name: 3

static bindings:

ip-address 10.10.1.2 mask 255.0.0.0

hardware-address 00e0-00fc-0001 ethernet

ip-address 10.10.1.3 mask 255.0.0.0

client-identifier aaaa-bbbb

expired unlimited

Table 5 Command output

Field	Description
Pool name	Name of an address pool.
Network	Assignable network.
secondary networks	Assignable secondary networks.
address range	Assignable address range.
class class-name range	DHCP user class and its address range.
static bindings	Static IP-to-MAC/client ID bindings.
option	Self-defined DHCP option.
expired	Lease duration: 1 2 3 4 in this example refers to 1 day 2 hours 3 minutes 4 seconds.
bootfile-name	Boot file name
dns-list	DNS server IP address.
domain-name	Domain name suffix.
bims-server	BIMS server information.
forbidden-ip	IP addresses excluded from dynamic allocation.
gateway-list	Gateway addresses.
nbns-list	WINS server addresses.
netbios-type	NetBIOS node type.
next-server	Next server IP address.
tftp-server domain-name	TFTP server name.
tftp-server ip-address	TFTP server address.
voice-config ncp-ip	Primary network calling processor address.
voice-config as-ip	Backup network calling processor address.
voice-config voice-vlan	Voice VLAN.
voice-config fail-over	Failover route.

display dhcp server statistics

Use display dhcp server statistics to display the DHCP server statistics.

Syntax

display dhcp server statistics [ pool pool-name ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

pool pool-name: Specifies an address pool by its name, a case-insensitive string of 1 to 63 characters. Without this option, the command displays information about all address pools.

Examples

# Display the DHCP server statistics.

<Sysname> display dhcp server statistics

Pool number: 1

Pool utilization: 0.39%

Bindings:

Automatic: 1

Manual: 0

Expired: 0

Conflict: 1

Messages received: 10

DHCPDISCOVER: 5

DHCPREQUEST: 3

DHCPDECLINE: 0

DHCPRELEASE: 2

DHCPINFORM: 0

BOOTPREQUEST: 0

Messages sent: 6

DHCPOFFER: 3

DHCPACK: 3

DHCPNAK: 0

BOOTPREPLY: 0

Bad Messages: 0

Table 6 Command output

Field	Description
Pool number	Total number of address pools. This field is not displayed when you display statistics for a specific address pool.
Pool utilization	Pool utilization rate: · If you display statistics for all address pools, this field displays the utilization rate of all address pools. · If you display statistics for an address pool, this field displays the pool utilization rate of the specified address pool.
Bindings	Bindings fall into the following types: · Automatic—Number of dynamic bindings. · Manual—Number of static bindings. · Expired—Number of expired bindings.
Conflict	Total number of conflict addresses. This field is not displayed if you display statistics for a specific address pool.
Messages received	DHCP packets received from clients: · DHCPDISCOVER · DHCPREQUEST · DHCPDECLINE · DHCPRELEASE · DHCPINFORM · BOOTPREQUEST This field is not displayed if you display statistics for a specific address pool.
Messages sent	DHCP packets sent to clients: · DHCPOFFER · DHCPACK · DHCPNAK · BOOTPREPLY This field is not displayed if statistics about a specific address pool are displayed.
Bad Messages	Number of bad messages. This field is not displayed if you display statistics for a specific address pool.

Related commands

reset dhcp server statistics

dns-list

Use dns-list to specify DNS server addresses in a DHCP address pool.

Use undo dns-list to remove DNS server addresses from a DHCP address pool.

Syntax

dns-list ip-address&<1-8>

undo dns-list [ ip-address&<1-8> ]

Default

No DNS server address is specified.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

ip-address&<1-8>: Specifies DNS servers. &<1-8> indicates that you can specify up to eight DNS server addresses separated by spaces.

Usage guidelines

If you use the dns-list command multiple times, the most recent configuration takes effect.

The undo dns-list command without any parameter specified deletes all DNS server addresses in the DHCP address pool.

Examples

# Specify the DNS server address 10.1.1.254 in DHCP address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] dns-list 10.1.1.254

Related commands

display dhcp server pool

domain-name

Use domain-name to specify a domain name in a DHCP address pool.

Use undo domain-name to remove the specified domain name.

Syntax

domain-name domain-name

undo domain-name

Default

No domain name suffix is specified.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

domain-name: Specifies the domain name, a case-insensitive string of 1 to 50 characters.

Usage guidelines

If you use the command multiple times, the most recent configuration takes effect.

Examples

# Specify the domain name company.com in address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] domain-name company.com

Related commands

display dhcp server pool

expired

Use expired to specify the lease duration in a DHCP address pool.

Use undo expired to restore the default lease duration for a DHCP address pool.

Syntax

expired { day day [ hour hour [ minute minute [ second second ] ] ] | unlimited }

undo expired

Default

The lease duration of a dynamic address pool is one day.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

day day: Specifies the number of days, in the range of 0 to 365.

hour hour: Specifies the number of hours, in the range of 0 to 23.

minute minute: Specifies the number of minutes, in the range of 0 to 59.

second second: Specifies the number of seconds, in the range of 0 to 59.

unlimited: Specifies the unlimited lease duration, which is actually 136 years.

Usage guidelines

The DHCP server assigns an IP address together with the lease duration to the DHCP client. Before the lease expires, the DHCP client must extend the lease duration. If the lease extension operation succeeds, the DHCP client can continue to use the IP address. If the lease option does not succeed, the DHCP client cannot use the IP address after the lease duration expires and the DHCP server will label the IP address as an expired address.

Examples

# Specify the lease duration as 1 day, 2 hours, 3 minutes, and 4 seconds in DHCP address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] expired day 1 hour 2 minute 3 second 4

Related commands

· display dhcp server expired

· display dhcp server pool

· reset dhcp server expired

forbidden-ip

Use forbidden-ip to exclude IP addresses from dynamic allocation in an address pool.

Use undo forbidden-ip to cancel the configuration.

Syntax

forbidden-ip ip-address&<1-8>

undo forbidden-ip [ ip-address&<1-8> ]

Default

No IP addresses are excluded from dynamic allocation in an address pool.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

ip-address&<1-8>: Specifies excluded IP addresses. &<1-8> indicates that you can specify up to eight IP addresses, separated by spaces.

Usage guidelines

The excluded IP addresses in an address pool are still assignable in other address pools.

You can exclude a maximum of 4096 IP addresses in an address pool.

The undo forbidden-ip command without any parameter specified deletes all excluded IP addresses.

Examples

# Exclude IP addresses 192.168.1.3 and 192.168.1.10 from dynamic allocation in DHCP address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] forbidden-ip 192.168.1.3 192.168.1.10

Related commands

· dhcp server forbidden-ip

· display dhcp server pool

gateway-list

Use gateway-list to specify gateway addresses in a DHCP address pool or a DHCP secondary subnet.

Use undo gateway-list to remove the specified gateway addresses from a DHCP address pool or a DHCP secondary subnet.

Syntax

gateway-list ip-address&<1-8>

undo gateway-list [ ip-address&<1-8> ]

Default

No gateway address is configured in a DHCP address pool or a DHCP secondary subnet.

Views

DHCP address pool view, DHCP secondary subnet view

Predefined user roles

network-admin

mdc-admin

Parameters

ip-address&<1-8>: Specifies gateways. &<1-8> indicates that you can specify up to eight gateway addresses separated by spaces. Gateway addresses must reside on the same subnet as the assignable IP addresses.

Usage guidelines

If you use this command multiple times, the most recent configuration takes effect.

The undo gateway-list command without any parameter deletes all gateway addresses.

If you specify gateways in both address pool view and secondary subnet view, DHCP assigns the gateway addresses in the secondary subnet view to the clients on the secondary subnet.

If you specify gateways in address pool view but not in secondary subnet view, DHCP assigns the gateway addresses in address pool view to the clients on the secondary subnet.

Examples

# Specify the gateway address 10.1.1.1 in DHCP address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] gateway-list 10.1.1.1

Related commands

display dhcp server pool

if-match option

Use if-match option to configure a match rule for a DHCP user class.

Use undo if-match option to remove the match rule for a DHCP user class.

Syntax

if-match option option-code [ hex hex-string [ mask mask | offset offset length length ] ]

undo if-match option option-code [ hex hex-string [ mask mask | offset offset length length ] ]

Default

No match rule is configured for the DHCP user class.

Views

DHCP user class view

Predefined user roles

network-admin

mdc-admin

Parameters

option-code: Matches a DHCP option identified by a number in the range of 1 to 254.

hex hex-string: Matches the specified string in the option, which must be a hex string of even numbers in the range of 2 to 256. If the hex-string argument is not specified, the DHCP server only checks whether the specified option exists in the received packets.

mask mask: Specifies the mask used to match the option content. The mask argument is a hex string of even numbers in the range of 2 to 256. The length of mask must be the same as that of hex-string.

offset offset: Specifies the offset to match the option, in the range of 0 to 254 bytes. If the offset argument is not specified, the server matches the entire option with the rule.

length length: Matches the specified length of the option, in the range of 1 to 128 bytes. The specified length must be the same as the hex-string length.

Usage guidelines

You can configure multiple match rules for a DHCP the user class.

The DHCP server matches DHCP requests against the match rules. A DHCP client matches the DHCP user class as long as it matches one of the specified rules.

The match operation follows these guidelines:

· If only the option-code argument is specified in the rule, packets containing the option match the rule.

· If only the option-code and hex-string arguments are specified in the rule, packets that have the specified hex string in the specified option match the rule.

· If the option-code, hex-string, offset and length arguments are specified in the rule, packets match the rule as long as their content from offset+1 bit to offset+length bit in the specified option is the same as the specified hex string.

· If the option-code, hex-string, and mask arguments are specified in the rule, the DHCP server ANDs the content from the first bit to the mask-1 bit in the specified option with the mask, and then compares the result with the result of the AND operation between hex-string and mask. If the two results are the same, the received packet matches the rule.

The option-code specified by different if-match option commands can be the same.

Examples

# Specify that packets containing Option 82 match the DHCP user class contain-option82.

<Sysname> system-view

[Sysname] dhcp server class contain-option82

[Sysname-dhcp-class-contain-option82] if-match option 82

# Specify that packets containing Option 82 whose first three bytes is 0x13ae92 match the DHCP user class exam.

<Sysname> system-view

[Sysname] dhcp server class exam

[Sysname-dhcp-class-exam] if-match option 82 hex 13ae92 offset 0 length 3

# Specify that packets containing Option 82 whose highest bit of the fourth byte is 1 match the DHCP user class exam.

<Sysname> system-view

[Sysname] dhcp class exam

[Sysname-dhcp-class-exam] if-match option 82 hex 00000080 mask 00000080

Related commands

dhcp class

nbns-list

Use nbns-list to specify WINS server addresses in a DHCP address pool.

Use undo nbns-list to remove the specified WINS server addresses.

Syntax

nbns-list ip-address&<1-8>

undo nbns-list [ ip-address&<1-8> ]

Default

No WINS server address is specified.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

ip-address&<1-8>: Specifies WINS server IP addresses. &<1-8> indicates that you can specify up to eight WINS server addresses separated by spaces.

Usage guidelines

If you use this command multiple times, the most recent configuration takes effect.

The undo nbns-list command with no parameter specified deletes all WINS server addresses.

Examples

# Specify the WINS server IP address 10.1.1.1 in DHCP address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] nbns-list 10.1.1.1

Related commands

· display dhcp server pool

· netbios-type

netbios-type

Use netbios-type to specify the NetBIOS node type in a DHCP address pool.

Use undo netbios-type to remove the specified NetBIOS node type.

Syntax

netbios-type { b-node | h-node | m-node | p-node }

undo netbios-type

Default

No NetBIOS node type is specified.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

b-node: Specifies the broadcast node. A b-node client sends the destination name in a broadcast message to get the name-to-IP mapping from a server.

h-node: Specifies the hybrid node. An h-node client unicasts the destination name to a WINS server. If it does not receive a response, the h-node client broadcasts the destination name to get the mapping from a server.

m-node: Specifies the mixed node. An m-node client broadcasts the destination name. If it does not receive a response, the m-node client unicasts the destination name to the WINS server to get the mapping.

p-node: Specifies the peer-to-peer node. A p-node client sends the destination name in a unicast message to get the mapping from the WINS server.

Usage guidelines

If you use the command multiple times, the most recent configuration takes effect.

Examples

# Specify the NetBIOS node type as p-node in DHCP address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] netbios-type p-node

Related commands

· display dhcp server pool

· nbns-list

network

Use network to specify the subnet for dynamic allocation in a DHCP address pool.

Use undo network to remove the specified subnet.

Syntax

network network-address [ mask-length | mask mask ] [ secondary ]

undo network network-address [ mask-length | mask mask ] [ secondary ]

Default

No subnet is specified in an address pool.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

network-address: Specifies the subnet for dynamic allocation. If no mask length or mask is specified, the natural mask will be used.

mask-length: Specifies the mask length in the range of 1 to 30.

mask mask: Specifies the mask in dotted decimal format.

secondary: Specifies the subnet as a secondary subnet. Without this keyword, this command specifies the primary subnet. If the addresses in the primary subnet are used up, the DHCP server can select addresses from a secondary subnet for the clients.

Usage guidelines

You can use the secondary keyword to specify a secondary subnet and enter its view, where you can specify gateways by using the gateway-list command for the DHCP clients in the secondary subnet.

You can specify only one primary subnet for a DHCP address pool. If you use the network command multiple times, the most recent configuration takes effect.

You can specify up to 32 secondary subnets for a DHCP address pool.

The primary subnet and secondary subnets in a DHCP address pool must not have the same network address and mask.

If you have used the address range or class command in an address pool, you cannot specify any secondary subnet in the same address pool.

Examples

# Specify primary subnet 192.168.8.0/24 and secondary subnet 192.168.10.0/24 in DHCP address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] network 192.168.8.0 mask 255.255.255.0

[Sysname-dhcp-pool-0] network 192.168.10.0 mask 255.255.255.0 secondary

[Sysname-dhcp-pool-0-secondary]

Related commands

· display dhcp server pool

· gateway-list

next-server

Use next-server to specify the IP address of a server in a DHCP address pool.

Use undo next-server to remove the server's IP address from the DHCP address pool.

Syntax

next-server ip-address

undo next-server

Default

No server's IP address is specified in an address pool.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

ip-address: Specifies the IP address of a server.

Usage guidelines

Upon startup, the DHCP client obtains its own IP address and the specified server IP address, and then contacts the specified server, such as a TFTP server, to get other boot information.

If you use the next-server command multiple times, the most recent configuration takes effect.

Examples

# Specify a server's IP address 10.1.1.254 in DHCP address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] next-server 10.1.1.254

Related commands

display dhcp server pool

option

Use option to configure a self-defined DHCP option in a DHCP address pool.

Use undo option to remove a self-defined DHCP option from a DHCP address pool.

Syntax

option code { ascii ascii-string | hex hex-string | ip-address ip-address&<1-8> }

undo option code

Default

No self-defined DHCP option is configured in a DHCP address pool.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

code: Specifies the number of the self-defined option, in the range of 2 to 254, excluding 12, 50 through 61, and 82.

ascii ascii-string: Specifies an ASCII string of 1 to 255 characters as the option content.

hex hex-string: Specifies a hex string of even numbers from 2 to 256 as the option content.

ip-address ip-address&<1-8>: Specifies the IP addresses as the option content. &<1-8> indicates that you can specify up to eight IP addresses separated by spaces.

Usage guidelines

The DHCP server fills the self-defined option with the specified ASCII string, hex string, or IP addresses, and sends it in a response to the client.

If you use the option command with the same code specified, the most recent configuration takes effect.

You can self-define options for the following purposes:

· Add newly released options.

· Add options for which the vendor defines the contents, for example, Option 43.

· Add options for which the CLI does not provide a dedicated configuration command. For example, you can use the option 4 ip-address 1.1.1.1 command to define the time server address 1.1.1.1 for DHCP clients.

· Add all option values if the actual requirement exceeds the limit for a dedicated option configuration command. For example, the dns-list command can specify up to eight DNS servers. To specify more than eight DNS server, you must use the option 6 command to define all DNS servers.

If a DHCP option is specified by both the dedicated command and the option command, the DHCP server preferentially assigns the content specified by the dedicated command. For example, if a DNS server address is specified by the dns-list command and the option 6 command, the server uses the address specified by dns-list command.

Examples

# Configure Option 7 to specify the log server address 2.2.2.2 in address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] option 7 ip-address 2.2.2.2

Related commands

display dhcp server pool

reset dhcp server conflict

Use reset dhcp server conflict to clear IP address conflict information.

Syntax

reset dhcp server conflict [ ip ip-address ]

Views

User view

Predefined user roles

network-admin

mdc-admin

Parameters

ip ip-address: Clears the conflict information for the specified IP address. If no IP address is specified, this command clears all address conflict information.

Usage guidelines

Address conflicts occur when dynamically assigned IP addresses have been statically configured for other hosts. After the conflicts are resolved, you can use the reset dhcp server conflict command to clear conflict information so that the conflicted addresses can be assigned to clients.

Examples

# Clear all IP address conflict information.

<Sysname> reset dhcp server conflict

Related commands

display dhcp server conflict

reset dhcp server expired

Use reset dhcp server expired to clear the binding information for expired IP addresses.

Syntax

reset dhcp server expired [ ip ip-address | pool pool-name ]

Views

User view

Predefined user roles

network-admin

mdc-admin

Parameters

ip ip-address: Clears the binding information for the specified expired IP address.

pool pool-name: Clears the binding information for the expired IP addresses in the specified address pool. The pool name is a case-insensitive string of 1 to 63 characters.

Usage guidelines

Using this command without any parameter clears binding information for all expired IP addresses.

Examples

# Clear the binding information for all expired IP addresses.

<Sysname> reset dhcp server expired

Related commands

display dhcp server expired

reset dhcp server ip-in-use

Use reset dhcp server ip-in-use to clear binding information for assigned IP addresses.

Syntax

reset dhcp server ip-in-use [ ip ip-address | pool pool-name ]

Views

User view

Predefined user roles

network-admin

mdc-admin

Parameters

ip ip-address: Clears the binding information for the specified assigned IP address.

pool pool-name: Clears the binding information for the specified address pool. The pool-name is a case-insensitive string of 1 to 63 characters.

Usage guidelines

Using this command without any parameter clears binding information for all assigned IP addresses.

If you use this command to clear information for an assigned static binding, the static binding becomes an unassigned static binding.

Examples

# Clear binding information for the IP address 10.110.1.1.

<Sysname> reset dhcp server ip-in-use ip 10.110.1.1

Related commands

display dhcp server ip-in-use

reset dhcp server statistics

Use reset dhcp server statistics to clear DHCP server statistics.

Syntax

reset dhcp server statistics

Views

User view

Predefined user roles

network-admin

mdc-admin

Examples

# Clear DHCP server statistics.

<Sysname> reset dhcp server statistics

Related commands

display dhcp server statistics

static-bind

Use static-bind to statically bind a client ID or MAC address to an IP address.

Use undo static-bind to remove a static binding.

Syntax

static-bind ip-address ip-address [ mask-length | mask mask ] { client-identifier client-identifier | hardware-address hardware-address [ ethernet | token-ring ] }

undo static-bind ip-address ip-address

Default

No static binding is specified in a DHCP address pool.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

ip-address ip-address: Specifies the IP address of the static binding. The natural mask is used if no mask length or mask is specified.

mask-length: Specifies the mask length in the range of 1 to 30.

mask mask: Specifies the mask, in dotted decimal format.

client-identifier client-identifier: Specifies the client ID of the static binding, a string of 4 to 254 characters that can contain only hexadecimal numbers and hyphen (-), in the format of H-H-H…., in which the last H can be a two-digit or four-digit hexadecimal number while the other Hs must be all four-digit hexadecimal numbers. For example, aabb-cccc-dd is a correct ID, while aabb-c-dddd and aabb-cc-dddd are incorrect IDs.

hardware-address hardware-address: Specifies the client hardware address of the static binding, a string of 4 to 79 characters that can contain only hexadecimal numbers and hyphen (-), in the format of H-H-H…, in which the last H can be a two-digit or four-digit hexadecimal number while the other Hs must be all four-digit hexadecimal numbers. For example, aabb-cccc-dd is a correct hardware address, while aabb-c-dddd and aabb-cc-dddd are incorrect hardware addresses.

ethernet: Specifies the client hardware address type as Ethernet. The default type is Ethernet.

token-ring: Specifies the client hardware address type as token ring.

Usage guidelines

The IP address of a static binding must not be an interface address of the DHCP server. Otherwise, an IP address conflict occurs, and the bound client cannot obtain the IP address.

You can specify multiple static bindings in an address pool. The total number of static bindings in all address pools cannot exceed 8192.

You cannot modify bindings. To change the binding for a DHCP client, you must delete the existing binding first and create a new binding.

Examples

# Bind the IP address 10.1.1.1/24 to the client ID 00aa-aabb in DHCP address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] static-bind ip-address 10.1.1.1 mask 255.255.255.0 client-identifier 00aa-aabb

Related commands

display dhcp server pool

tftp-server domain-name

Use tftp-server domain-name to specify a TFTP server name in a DHCP address pool.

Use undo tftp-server domain-name to remove the TFTP server name from a DHCP address pool.

Syntax

tftp-server domain-name domain-name

undo tftp-server domain-name

Default

No TFTP server name is specified.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

domain-name: Specifies the TFTP server name, a case-sensitive string of 1 to 63 characters.

Usage guidelines

If you use this command multiple times, the most recent configuration takes effect.

Examples

# Specify the TFTP server name aaa in DHCP address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] tftp-server domain-name aaa

Related commands

· display dhcp server pool

· tftp-server ip-address

tftp-server ip-address

Use tftp-server ip-address to specify a TFTP server address in a DHCP address pool.

Use undo tftp-server ip-address to remove the TFTP server address from a DHCP address pool.

Syntax

tftp-server ip-address ip-address

undo tftp-server ip-address

Default

No TFTP server address is specified.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

ip-address: Specifies the IP address of a TFTP server.

Usage guidelines

If you use this command multiple times, the most recent configuration takes effect.

Examples

# Specify the TFTP server address 10.1.1.1 in DHCP address pool 0.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] tftp-server ip-address 10.1.1.1

Related commands

· display dhcp server pool

· tftp-server domain-name

voice-config

Use voice-config to configure the content for Option 184 in a DHCP address pool.

Use undo voice-config to remove the Option 184 content from a DHCP address pool.

Syntax

voice-config { as-ip ip-address | fail-over ip-address dialer-string | ncp-ip ip-address | voice-vlan vlan-id { disable | enable } }

undo voice-config [ as-ip | fail-over | ncp-ip | voice-vlan ]

Default

No Option 184 content is configured in a DHCP address pool.

Views

DHCP address pool view

Predefined user roles

network-admin

mdc-admin

Parameters

as-ip ip-address: Specifies the IP address of the backup network calling processor.

fail-over ip-address dialer-string: Specifies the failover IP address and dialer string. The dialer-string is a string of 1 to 39 characters, which can include numbers 0 through 9 and asterisk (*).

ncp-ip ip-address: Specifies the IP address of the primary network calling processor.

voice-vlan vlan-id: Specifies the voice VLAN ID in the range of 2 to 4094.

· disable: Disables the specified VLAN. DHCP clients will not take this VLAN as their voice VLAN.

· enable: Enables the specified VLAN. DHCP clients will take this VLAN as their voice VLAN.

Usage guidelines

If you use the command multiple times, the most recent configuration takes effect.

Examples

# Configure Option 184 in DHCP address pool 0: the primary network calling processor 10.1.1.1, backup network calling processor 10.2.2.2, voice VLAN 3 that is enabled, failover IP address 10.3.3.3, and dialer string 99*.

<Sysname> system-view

[Sysname] dhcp server ip-pool 0

[Sysname-dhcp-pool-0] voice-config ncp-ip 10.1.1.1

[Sysname-dhcp-pool-0] voice-config as-ip 10.2.2.2

[Sysname-dhcp-pool-0] voice-config voice-vlan 3 enable

[Sysname-dhcp-pool-0] voice-config fail-over 10.3.3.3 99*

Related commands

display dhcp server pool

DHCP relay agent commands

dhcp relay check mac-address

Use dhcp relay check mac-address to enable MAC address check on the relay agent.

Use undo dhcp relay check mac-address to disable MAC address check on the relay agent.

Syntax

dhcp relay check mac-address

undo dhcp relay check mac-address

Default

The MAC address check function is disabled.

Views

Interface view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

With this function enabled, the DHCP relay agent compares the chaddr field of a received DHCP request with the source MAC address in the frame header. If they are the same, the DHCP relay agent forwards the request to the DHCP server. If they are not the same, the DHCP relay agent discards the DHCP request.

The MAC address check function takes effect only when the dhcp select relay command has been configured on the interface.

A DHCP relay agent changes the source MAC addresses of DHCP packets before forwarding them out. Therefore, enable MAC address check only on the DHCP relay agent directly connected to the DHCP clients. If you enable this feature on an intermediate relay agent, it may discard valid DHCP packets and the sending clients will not obtain IP addresses.

Examples

# Enable MAC address check on the relay agent.

<Sysname> system-view

[Sysname] interface vlan-interface 10

[Sysname-Vlan-interface10] dhcp relay check mac-address

Related commands

dhcp select relay

dhcp relay client-information record

Use dhcp relay client-information record to enable recording client information in relay entries. A relay entry contains information about a client such as the client's IP and MAC addresses.

Use undo dhcp relay client-information record to disable the function.

Syntax

dhcp relay client-information record

undo dhcp relay client-information record

Default

The DHCP relay agent does not record client information in relay entries.

Views

System view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

Disabling recording of client information deletes all recorded relay entries.

Examples

# Enable recording of relay entries on the relay agent.

<Sysname> system-view

[Sysname] dhcp relay client-information record

Related commands

· dhcp relay client-information refresh

· dhcp relay client-information refresh enable

dhcp relay client-information refresh

Use dhcp relay client-information refresh to configure the interval at which the DHCP relay agent periodically refreshes relay entries.

Use undo dhcp relay client-information refresh to restore the default.

Syntax

dhcp relay client-information refresh [ auto | interval interval ]

undo dhcp relay client-information refresh

Default

The refresh interval is automatically calculated based on the number of relay entries.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

auto: Automatically calculates the refresh interval based on the number of entries. The more entries, the shorter the refresh interval. The shortest interval must not be less than 500 ms.

interval interval: Specifies the refresh interval in the range of 1 to 120 seconds.

Usage guidelines

If you use this command multiple times, the most recent configuration takes effect.

Examples

# Set the refresh interval to 100 seconds.

<Sysname> system-view

[Sysname] dhcp relay client-information refresh interval 100

Related commands

· dhcp relay client-information record

· dhcp relay client-information refresh enable

dhcp relay client-information refresh enable

Use dhcp relay client-information refresh enable to enable the relay agent to periodically refresh dynamic relay entries.

Use undo dhcp relay client-information refresh enable to disable the relay agent to periodically refresh dynamic relay entries.

Syntax

dhcp relay client-information refresh enable

undo dhcp relay client-information refresh enable

Default

The DHCP relay agent periodically refreshes relay entries.

Views

System view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

A DHCP client unicasts a DHCP-RELEASE message to the DHCP server to release its IP address. The DHCP relay agent conveys the message to the DHCP server and does not remove the IP-to-MAC entry of the client.

With this feature, the DHCP relay agent uses the IP address of a client and the MAC address of the DHCP relay interface to periodically send a DHCP-REQUEST message to the DHCP server.

· If the server returns a DHCP-ACK message or does not return any message within a specific interval, the DHCP relay agent removes the entry and sends a DHCP-RELEASE message to the DHCP server to release the IP address.

· If the server returns a DHCP-NAK message, the relay agent keeps the entry.

With this feature disabled, the DHCP relay agent does not remove relay entries automatically. After a DHCP client releases its IP address, you must use the reset dhcp relay client-information on the relay agent to remove the corresponding relay entry.

Examples

# Disable periodic refresh of relay entries.

<Sysname> system-view

[Sysname] undo dhcp relay client-information refresh enable

Related commands

· dhcp relay client-information record

· dhcp relay client-information refresh

· reset dhcp relay client-information

dhcp relay information circuit-id

Use dhcp relay information circuit-id to configure the padding content and padding format for the circuit ID sub-option of Option 82.

Use undo dhcp relay information circuit-id to restore the default.

Syntax

dhcp relay information circuit-id { string circuit-id | { normal | verbose [ node-identifier { mac | sysname | user-defined node-identifier } ] } [ format { ascii | hex } ] }

undo dhcp relay information circuit-id

Default

The content mode is normal and the padding format is hex.

Views

Interface view

Predefined user roles

network-admin

mdc-admin

Parameters

string circuit-id: Specifies a case-sensitive string of 3 to 63 characters as the content of the circuit ID sub-option.

normal: Specifies the normal mode, in which the padding content consists of the VLAN ID and port number.

verbose: Specifies the verbose mode.

node-identifier { mac | sysname | user-defined node-identifier }: Specifies the access node identifier. By default, the node MAC address is used as the node identifier.

· mac: Uses the node MAC address as the node identifier. The padding content is a character string composed of the MAC address, Ethernet type (the value is "eth"), chassis number, slot number, sub-slot number, interface number, and VLAN ID.

· sysname: Uses the node name as the node identifier. The padding content is a character string composed of the system name, Ethernet type (fixed to "eth"), chassis number, slot number, sub-slot number, interface number, and VLAN ID. You can specify the system name by using the sysname command in system view. The padding format of the system name is always ASCII.

· user-defined node-identifier: Uses a case-sensitive string of 1 to 50 characters as the node identifier. The padding content contains the specified character string, Ethernet type (fixed to "eth"), chassis number, slot number, sub-slot number, interface number, and VLAN ID. The padding format of the specified character string is always ASCII regardless of the specified padding format.

format: Specifies the padding format.

ascii: Specifies the ASCII padding format.

hex: Specifies the Hex padding format.

Usage guidelines

The padding format depends on the padding content:

· The padding format for the specified character string is always ASCII.

· The padding format for the normal and verbose modes is determined by the command.

If no padding format is specified:

· In normal mode, the padding format for VLAN ID and port number is Hex.

· In verbose mode, the padding format for the node identifier (MAC address, system name, or the specified node identifier), Ethernet type, chassis number, slot number, sub-slot number, interface number is ASCII, and the padding format for VLAN ID is Hex.

If ascii is specified, all the content is padded in ASCII format.

If hex is specified:

· In normal mode, the padding format for VLAN ID and port number is Hex.

· In verbose mode, the padding format for the node identifier and Ethernet type is ASCII, and the padding format for other padding content is Hex.

If you use this command multiple times, the most recent configuration takes effect.

Examples

# Specify the content mode as verbose, node identifier as the system name, and the padding format as ASCII for the circuit ID sub-option.

<Sysname> system-view

[Sysname] interface vlan-interface 10

[Sysname-Vlan-interface10] dhcp relay information enable

[Sysname-Vlan-interface10] dhcp relay information strategy replace

[Sysname-Vlan-interface10] dhcp relay information circuit-id verbose node-identifier sysname format ascii

Related commands

· dhcp relay information enable

· dhcp relay information strategy

· display dhcp relay information

dhcp relay information enable

Use dhcp relay information enable to enable the relay agent to support Option 82.

Use undo dhcp relay information enable to disable Option 82 support.

Syntax

dhcp relay information enable

undo dhcp relay information enable

Default

The DHCP relay agent does not support Option 82.

Views

Interface view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

With this feature enabled, the DHCP relay agent adds Option 82 to a DHCP request that does not contain Option 82 before forwarding it to the DHCP server. You can configure the content of Option 82 with the dhcp relay information circuit-id and dhcp relay information remote-id commands. If the DHCP request contains Option 82, the relay agent handles the request according to the strategy specified by the dhcp relay information strategy command.

With this feature disabled, the relay agent does not add or handle Option 82.

Examples

# Enable Option 82 support on the relay agent.

<Sysname> system-view

[Sysname] interface vlan-interface 10

[Sysname-Vlan-interface10] dhcp relay information enable

Related commands

· dhcp relay information circuit-id

· dhcp relay information remote-id

· dhcp relay information strategy

· display dhcp relay information

dhcp relay information remote-id

Use dhcp relay information remote-id to configure the padding content and padding format for the remote ID sub-option of Option 82.

Use undo dhcp relay information remote-id to restore the default.

Syntax

dhcp relay information remote-id { normal [ format { ascii | hex } ] | string remote-id | sysname }

undo dhcp relay information remote-id

Default

The content mode is normal and the padding format is hex.

Views

Interface view

Predefined user roles

network-admin

mdc-admin

Parameters

normal: Specifies the normal mode in which the padding content is the MAC address of the receiving interface.

format: Specifies the padding format. The default setting is Hex.

ascii: Specifies the ASCII padding format.

hex: Specifies the Hex padding format.

string remote-id: Specifies a case-sensitive string of 1 to 63 characters as the content of the remote ID sub-option.

sysname: Uses the system name as the content of the remote ID sub-option. You can set the system name by using the sysname command.

Usage guidelines

The padding format for the specified character string (string) or the system name (sysname) is always ASCII. The padding format for the normal mode is determined by the command.

If you use the command multiple times, the most recent configuration takes effect.

Examples

# Specify the padding content for the remote ID sub-option of Option 82 as device001.

<Sysname> system-view

[Sysname] interface vlan-interface 10

[Sysname-Vlan-interface10] dhcp relay information enable

[Sysname-Vlan-interface10] dhcp relay information strategy replace

[Sysname-Vlan-interface10] dhcp relay information remote-id string device001

Related commands

· dhcp relay information enable

· dhcp relay information strategy

· display dhcp relay information

dhcp relay information strategy

Use dhcp relay information strategy to configure the strategy for the DHCP relay agent to handle messages containing Option 82.

Use undo dhcp relay information strategy to restore the default handling strategy.

Syntax

dhcp relay information strategy { drop | keep | replace }

undo dhcp relay information strategy

Default

The handling strategy for messages containing Option 82 is replace.

Views

Interface view

Predefined user roles

network-admin

mdc-admin

Parameters

drop: Drops messages containing Option 82.

keep: Does not change Option 82.

replace: Replaces the original Option 82 with the configured Option 82.

Usage guidelines

This command takes effect only for DHCP requests containing Option 82.

If the DHCP relay agent is enabled to support Option 82, it will always add Option 82 into the DHCP requests that do not contain Option 82 before forwarding the requests to the DHCP server.

Examples

# Configure the handling strategy for Option 82 as keep.

<Sysname> system-view

[Sysname] interface vlan-interface 10

[Sysname-Vlan-interface10] dhcp relay information enable

[Sysname-Vlan-interface10] dhcp relay information strategy keep

Related commands

· dhcp relay information enable

· display dhcp relay information

dhcp relay release ip

Use dhcp relay release ip to release a specific client IP address.

Syntax

dhcp relay release ip client-ip [ vpn-instance vpn-instance-name ]

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

client-ip: Specifies the IP address to be released.

vpn-instance vpn-instance-name: Specifies the MPLS L3VPN of the IP address. The vpn-instance-name is a case-sensitive string of 1 to 31 characters. If no VPN is specified, the IP address in the public network will be released.

Usage guidelines

After you execute this command, the relay agent sends a DHCP-RELEASE packet to the DHCP server and removes the relay entry of the IP address. Upon receiving the packet, the server removes the binding information for the specified IP address to release the IP address.

Examples

# Release the IP address 1.1.1.1.

<Sysname> system-view

[Sysname] dhcp relay release ip 1.1.1.1

dhcp relay server-address

Use dhcp relay server-address to specify DHCP servers on the DHCP relay agent.

Use undo dhcp relay server-address to remove DHCP servers.

Syntax

dhcp relay server-address ip-address

undo dhcp relay server-address [ ip-address ]

Default

No DHCP server is specified on the relay agent.

Views

Interface view

Predefined user roles

network-admin

mdc-admin

Parameters

ip-address: Specifies the IP address of a DHCP server. The DHCP relay agent forwards DHCP packets received from DHCP clients to this DHCP server.

Usage guidelines

The specified IP address of the DHCP server must not reside on the same subnet as the IP address of the DHCP relay agent interface. Otherwise, the DHCP clients may fail to obtain IP addresses.

You can specify a maximum of eight DHCP servers on an interface. The DHCP relay agent forwards the packets from the clients to all the specified DHCP servers.

If no IP address is specified, the undo dhcp relay server-address command removes all DHCP servers on the interface.

Examples

# Specify the DHCP server 1.1.1.1 on the relay agent interface VLAN-interface 10.

<Sysname> system-view

[Sysname] interface vlan-interface 10

[Sysname-Vlan-interface10] dhcp relay server-address 1.1.1.1

Related commands

· dhcp select relay

· display dhcp relay interface

display dhcp relay client-information

Use display dhcp relay client-information to display relay entries on the relay agent.

Syntax

display dhcp relay client-information [ interface interface-type interface-number | ip ip-address [ vpn-instance vpn-instance-name ] ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

interface interface-type interface-number: Displays relay entries on the specified interface.

ip ip-address: Displays the relay entry for the specified IP address.

vpn-instance vpn-instance-name: Displays the relay entry for the specified IP address in the specified MPLS L3VPN. The vpn-instance-name is a case-sensitive string of 1 to 31 characters.

Usage guidelines

The DHCP relay agent records relay entries only when the dhcp relay client-information record command has been issued.

Without any parameter specified, the display dhcp relay client-information command shows all relay entries on the relay agent.

Examples

# Display all relay entries on the relay agent.

<Sysname> display dhcp relay client-information

Total number of client-information items: 2

Total number of dynamic items: 1

Total number of temporary items: 1

IP address MAC address Type Interface VPN name

10.1.1.1 00e0-0000-0001 Dynamic GigabitEthernet3/0/1 VPN1

10.1.1.5 00e0-0000-0000 Temporary Vlan2 VPN2

Table 7 Command output

Field	Description
Total number of client-information items	Total number of relay entries.
Total number of dynamic items	Total number of dynamic relay entries.
Total number of temporary items	Total number of temporary relay entries.
IP address	IP address of the DHCP client.
MAC address	MAC address of the DHCP client.
Type	Relay entry type: · Dynamic—The relay agent creates a dynamic relay entry upon receiving an ACK response from the DHCP server. · Temporary—The relay agent creates a temporary relay entry upon receiving a REQUEST packet from a DHCP client.
Interface	Layer-3 interface connected to the DHCP client. N/A is displayed for relay entries without interface information.

Related commands

· dhcp relay client-information record

· reset dhcp relay client-information

display dhcp relay information

Use display dhcp relay information to display Option 82 configuration information on the DHCP relay agent.

Syntax

display dhcp relay information [ interface interface-type interface-number ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

interface interface-type interface-number: Displays Option 82 configuration information on the specified interface. If you do not specify any interface, the command displays Option 82 configuration information for all interfaces.

Examples

# Display the Option 82 configuration information for all interfaces.

<Sysname> display dhcp relay information

Interface: Vlan-interface100

Status: Enable

Strategy: Replace

Circuit ID Pattern: Verbose

Remote ID Pattern: Sysname

Circuit ID format-type: Undefined

Remote ID format-type: ASCII

Node identifier: aabbcc

Interface: Vlan-interface200

Status: Enable

Strategy: Replace

Circuit ID Pattern: User Defined

Remote ID Pattern: User Defined

Circuit ID format-type: ASCII

Remote ID format-type: ASCII

User defined:

Circuit ID: vlan100

Remote ID: device001

Table 8 Command output

Field			Description
Interface			Interface name.
Status		Option 82 states: · Enable—DHCP relay agent support for Option 82 is enabled. · Disable—DHCP relay agent support for Option 82 is disabled.
Strategy	Handling strategy for request messages containing Option 82, Drop, Keep, or Replace.
Circuit ID Pattern	Padding content mode of the circuit ID sub-option, Verbose, Normal, or User Defined.
Remote ID Pattern	Padding content mode of the remote ID sub-option, Sysname, Normal, or User Defined.
Circuit ID format-type	Padding format of the circuit ID sub-option, ASCII, Hex, or Undefined.
Remote ID format-type	Padding format of the remote ID sub-option, ASCII, Hex, or Undefined.
Node identifier				Access node identifier.
User defined				Content of the user-defined sub-options.
Circuit ID				User-defined content of the circuit ID sub-option.
Remote ID				User-defined content of the remote ID sub-option.

display dhcp relay server-address

Use display dhcp relay server-address to display DHCP server addresses configured on an interface operating in DHCP relay agent mode.

Syntax

display dhcp relay server-address [ interface interface-type interface-number ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

interface interface-type interface-number: Displays DHCP server addresses on the specified interface. If you do not specify any interface, the command displays DHCP server addresses on all interfaces operating in DHCP relay agent mode.

Examples

# Display DHCP server addresses on all interfaces operating in DHCP relay agent mode.

<Sysname> display dhcp relay server-address

Interface name Server IP address

GigabitEthernet3/0/1 2.2.2.2

Table 9 Command output

Field	Description
Server IP address	DHCP server IP address specified on the DHCP relay agent.

Related commands

dhcp relay server-address

display dhcp relay statistics

Use display dhcp relay statistics to display DHCP packet statistics on the DHCP relay agent.

Syntax

display dhcp relay statistics [ interface interface-type interface-number ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

interface interface-type interface-number: Displays DHCP packet statistics on the specified interface. If no interface is specified, the command displays all DHCP packet statistics on the DHCP relay agent.

Examples

# Display all DHCP packet statistics on the DHCP relay agent.

<Sysname> display dhcp relay statistics

DHCP packets dropped: 0

DHCP packets received from clients: 0

DHCPDISCOVER: 0

DHCPREQUEST: 0

DHCPINFORM: 0

DHCPRELEASE: 0

DHCPDECLINE: 0

BOOTPREQUEST: 0

DHCP packets received from servers: 0

DHCPOFFER: 0

DHCPACK: 0

DHCPNAK: 0

BOOTPREPLY: 0

DHCP packets relayed to servers: 0

DHCPDISCOVER: 0

DHCPREQUEST: 0

DHCPINFORM: 0

DHCPRELEASE: 0

DHCPDECLINE: 0

BOOTPREQUEST: 0

DHCP packets relayed to clients: 0

DHCPOFFER: 0

DHCPACK: 0

DHCPNAK: 0

BOOTPREPLY: 0

DHCP packets sent to servers: 0

DHCPDISCOVER: 0

DHCPREQUEST: 0

DHCPINFORM: 0

DHCPRELEASE: 0

DHCPDECLINE: 0

BOOTPREQUEST: 0

DHCP packets sent to clients: 0

DHCPOFFER: 0

DHCPACK: 0

DHCPNAK: 0

BOOTPREPLY: 0

Related commands

reset dhcp relay statistics

reset dhcp relay client-information

Use reset dhcp relay client-information to clear relay entries on the DHCP relay agent.

Syntax

reset dhcp relay client-information [ interface interface-type interface-number | ip ip-address [ vpn-instance vpn-instance-name ] ]

Views

User view

Predefined user roles

network-admin

mdc-admin

Parameters

interface interface-type interface-number: Clears relay entries on the specified interface.

ip ip-address: Clears the relay entry for the specified IP address.

vpn-instance vpn-instance-name: Clears the relay entry for the specified IP address in the specified MPLS L3VPN. The vpn-instance-name is a case-sensitive string of 1 to 31 characters. If you do not specify any VPN, the command clears the relay entry in the public network.

Usage guidelines

If you do not specify any parameter, this command clears all relay entries on the DHCP relay agent.

Examples

# Clear all relay entries on the DHCP relay agent.

<Sysname> reset dhcp relay client-information

Related commands

display dhcp relay client-information

reset dhcp relay statistics

Use reset dhcp relay statistics to clear relay agent statistics.

Syntax

reset dhcp relay statistics [ interface interface-type interface-number ]

Views

User view

Predefined user roles

network-admin

mdc-admin

Parameters

interface interface-type interface-number: Clears DHCP relay agent statistics on the specified interface. If you do not specify any interface, this command clears all DHCP relay agent statistics.

Examples

# Clear all DHCP relay agent statistics.

<Sysname> reset dhcp relay statistics

Related commands

display dhcp relay statistics

DHCP snooping commands

DHCP snooping works between the DHCP client and the DHCP server or between the DHCP client and the relay agent. DHCP snooping does not work between the DHCP server and the DHCP relay agent.

dhcp snooping binding database filename

Use dhcp snooping binding database filename to specify a file to store DHCP snooping entries.

Use undo dhcp snooping binding database filename to restore the default.

Syntax

dhcp snooping binding database filename filename

undo dhcp snooping binding database filename

Default

No file is specified.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

filename: Specifies a file by its name. For information about the filename argument, see Fundamentals Configuration Guide.

Usage guidelines

If the specified file does not exist, the device automatically creates the file to store DHCP snooping entries.

This command enables the device to save DHCP snooping entries in the specified file immediately. After that, if no update interval is specified with the dhcp snooping binding database update interval command, the device does not update the file until 300 seconds after a DHCP snooping entries change. If an update interval is set, the device updates DHCP snooping entries at the specified interval.

Examples

# Specify the file database.dhcp to store DHCP snooping entries.

<Sysname> system-view

[Sysname] dhcp snooping binding database filename database.dhcp

Related commands

dhcp snooping binding database update interval

Use dhcp snooping binding database update interval to set the interval at which the device updates DHCP snooping entries.

Use undo dhcp snooping binding database update interval to restore the default.

Syntax

dhcp snooping binding database update interval seconds

undo dhcp snooping binding database update interval

Default

The interval is 300 seconds.

Views

System view

Predefined user roles

network-admin

mdc-admin

Parameters

Seconds: Sets the update interval in the range of 60 to 864000 seconds.

Usage guidelines

This command enables updating DHCP snooping entries at the specified interval. If a DHCP snooping entry is learned or removed during an interval, DHCP snooping adds or removes this entry at the end of this interval. If no change occurs within the interval, DHCP snooping does not perform the update operation.

This command does not take effect if the file for storing DHCP snooping entries is not specified with the dhcp snooping binding database filename command.

Examples

# Set the interval to update DHCP snooping entries to 10 minutes (600 seconds).

<Sysname> system-view

[Sysname] dhcp snooping binding database update interval 600

Related commands

dhcp snooping binding database filename

dhcp snooping binding database update now

Use dhcp snooping binding database update now to manually save DHCP snooping entries to the file.

Syntax

dhcp snooping binding database update now

Views

System view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

Use this command to manually save DHCP snooping entries into the file specified by the dhcp snooping binding database filename command. If no file has been specified, this command does not take effect.

Examples

# Save DHCP snooping entries to the file.

<Sysname> system-view

[Sysname] dhcp snooping binding database update now

Related commands

dhcp snooping binding database filename

dhcp snooping binding record

Use dhcp snooping binding record to enable recording of client information in DHCP snooping entries.

Use undo dhcp snooping binding record to disable the function.

Syntax

dhcp snooping binding record

undo dhcp snooping binding record

Default

DHCP snooping does not record client information.

Views

Layer 2 Ethernet interface view, Layer 2 aggregate interface view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

This command enables DHCP snooping on the port directly connected to the clients to record client information in DHCP snooping entries.

Examples

# Enable recording of client information in DHCP snooping entries.

<Sysname> system-view

[Sysname] interface GigabitEthernet 3/0/1

[Sysname-GigabitEthernet3/0/1] dhcp snooping binding record

dhcp snooping check mac-address

Use dhcp snooping check mac-address to enable MAC address check for DHCP snooping.

Use undo dhcp snooping check mac-address to disable MAC address check for DHCP snooping.

Syntax

dhcp snooping check mac-address

undo dhcp snooping check mac-address

Default

This function is disabled.

Views

Layer 2 Ethernet interface view, Layer 2 aggregate interface view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

With MAC address check enabled, DHCP snooping compares the chaddr field of a received DHCP request with the source MAC address field in the frame header. If they are the same, DHCP snooping considers this request valid and forwards it to the DHCP server. If they are not the same, DHCP snooping discards the DHCP request.

Examples

# Enable MAC address check for DHCP snooping.

<Sysname> system-view

[Sysname] interface GigabitEthernet 3/0/1

[Sysname-GigabitEthernet3/0/1] dhcp snooping check mac-address

dhcp snooping check request-message

Use dhcp snooping check request-message to enable DHCP-REQUEST check for DHCP snooping.

Use undo dhcp snooping check request-message to disable DHCP-REQUEST check for DHCP snooping.

Syntax

dhcp snooping check request-message

undo dhcp snooping check request-message

Default

This function is disabled.

Views

Layer 2 Ethernet interface view, Layer 2 aggregate interface view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

DHCP-REQUEST packets include lease renewal packets, DHCP-DECLINE packets, and DHCP-RELEASE packets. This function prevents unauthorized clients that forge DHCP-REQUEST packets from attacking the DHCP server.

With this function enabled, DHCP snooping looks for a matching DHCP snooping entry for each received DHCP-REQUEST message.

· If a match is found, DHCP snooping compares the entry with the message. If they have consistent information, DHCP snooping considers the packet valid and forwards it to the DHCP server. If they have different information, DHCP snooping considers the message invalid and discards it.

· If no match is found, DHCP snooping forwards the message to the DHCP server.

Examples

# Enable DHCP-REQUEST check for DHCP snooping.

<Sysname> system-view

[Sysname] interface GigabitEthernet3/0/1

[Sysname-GigabitEthernet3/0/1] dhcp snooping check request-message

dhcp snooping enable

Use dhcp snooping enable to enable DHCP snooping.

Use undo dhcp snooping enable to disable DHCP snooping.

Syntax

dhcp snooping enable

undo dhcp snooping enable

Default

DHCP snooping is disabled.

Views

System view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

When DHCP snooping is disabled, the device forwards all responses received from DHCP servers and does not record DHCP client information.

Examples

# Enable DHCP snooping.

<Sysname> system-view

[Sysname] dhcp snooping enable

dhcp snooping information circuit-id

Use dhcp snooping information circuit-id to configure the padding content and code type for the circuit ID sub-option.

Use undo dhcp snooping information circuit-id to restore the default.

Syntax

dhcp snooping information circuit-id { [ vlan vlan-id ] string circuit-id | { normal | verbose [ node-identifier { mac | sysname | user-defined node-identifier } ] } [ format { ascii | hex } ] }

undo dhcp snooping information circuit-id [ vlan vlan-id ]

Default

The padding format is normal and the code type is hex.

Views

Layer 2 Ethernet interface view, Layer 2 aggregate interface view

Predefined user roles

network-admin

mdc-admin

Parameters

vlan vlan-id: Specifies a user-defined VLAN ID for the circuit ID sub-option.

string circuit-id: Specifies the padding content for the circuit ID sub-option, a case-sensitive string of 3 to 63 characters.

normal: Specifies the normal padding format.

verbose: Specifies the verbose padding format.

node-identifier { mac | sysname | user-defined node-identifier }: Specifies the access node identifier. By default, the node MAC address is used as the node identifier.

· mac: Uses the node MAC address as the node identifier. The padding content is a character string comprising the node MAC address, Ethernet type (fixed to "eth"), chassis number, slot number, sub-slot number, interface number, and VLAN ID.

· sysname: Uses the system name as the node identifier. The padding content is a character string comprising the system name, Ethernet type (fixed to "eth"), chassis number, slot number, sub-slot number, interface number, and VLAN ID. The system name can be configured with the sysname command in system view. No matter which code type is specified, the system name is padded in ASCII.

· user-defined node-identifier: Specifies a node identifier, a case-sensitive string of 1 to 50 characters. The padding content is a character string comprising the specified string, Ethernet type (fixed to "eth"), chassis number, slot number, sub-slot number, interface number, and VLAN ID. No matter which code type is specified, the specified string is padded in ASCII.

format: Specifies the code type for the circuit ID sub-option.

ascii: Specifies the ASCII code type.

hex: Specifies the hex code type.

Usage guidelines

DHCP snooping uses ASCII to pad the circuit ID sub-option comprising a user-defined node identifier.

If normal or verbose is specified as the padding format, the code type is determined as follows:

· If no code type is specified, for normal padding format, hex is adopted for VLAN ID and port number. For verbose padding format, ASCII is adopted for node identifier (MAC address, system name, or the specified string), Ethernet type, chassis number, slot number, sub-slot number, and interface number, and hex is adopted for VLAN ID.

· If ascii is specified as the code type, all content is padded in ASCII.

· If hex is specified as the code type, for normal padding format, hex is adopted for VLAN ID and port number. For verbose padding format, ASCII is adopted for node identifier and Ethernet type, and hex is adopted for other content.

If you use this command multiple times, the most recent configuration takes effect.

If replace is configured as the handling strategy for DHCP requests containing Option 82, you need to configure the padding content and code type for the circuit ID sub-option. If the handling strategy is keep or drop, you do not need to configure the padding content and code type for the circuit ID sub-option.

Examples

# Configure verbose as the padding format, system name as the node identifier, and ASCII as the code type for the circuit ID sub-option.

<Sysname> system-view

[Sysname] interface vlan-interface 10

[Sysname-Vlan-interface10] dhcp snooping information enable

[Sysname-Vlan-interface10] dhcp snooping information strategy replace

[Sysname-Vlan-interface10] dhcp snooping information circuit-id verbose node-identifier sysname format ascii

Related commands

· dhcp snooping information enable

· dhcp snooping information strategy

· display dhcp snooping information

dhcp snooping information enable

Use dhcp snooping information enable to enable DHCP snooping to support Option 82.

Use undo dhcp snooping information enable to disable this function.

Syntax

dhcp snooping information enable

undo dhcp snooping information enable

Default

DHCP snooping does not support Option 82.

Views

Layer 2 Ethernet interface view, Layer 2 aggregate interface view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

This command enables DHCP snooping to add Option 82 into DHCP request packets forwarded to the DHCP server. The content of Option 82 is determined by the dhcp snooping information circuit-id and dhcp snooping information remote-id commands. If the received DHCP request packets contain Option 82, DHCP snooping handles the packets according to the strategy configured with the dhcp snooping information strategy command.

Examples

# Enable DHCP snooping to support Option 82.

<Sysname> system-view

[Sysname] interface GigabitEthernet 3/0/1

[Sysname-GigabitEthernet3/0/1] dhcp snooping information enable

Related commands

· dhcp snooping information circuit-id

· dhcp snooping information remote-id

· dhcp snooping information strategy

dhcp snooping information remote-id

Use dhcp snooping information remote-id to configure the padding content and code type for the remote ID sub-option.

Use undo dhcp snooping information remote-id to restore the default.

Syntax

dhcp snooping information remote-id { [ vlan vlan-id ] string { remote-id | sysname } | normal [ format { ascii | hex } ] }

undo dhcp snooping information remote-id [vlan vlan-id ]

Default

The padding format is normal and the code type is hex.

Views

Layer 2 Ethernet interface view, Layer 2 aggregate interface view

Predefined user roles

network-admin

mdc-admin

Parameters

vlan vlan-id: Specifies a user-defined VLAN ID as the remote ID sub-option.

string remote-id: Specifies the character string as the remote ID sub-option, a case-sensitive string of 1 to 63 characters.

sysname: Specifies the system name as the remote ID sub-option. You can configure the system name with the sysname command in system view.

normal: Specifies the normal padding format. The padding content is the MAC address of the receiving interface.

format: Specifies the code type for the remote ID sub-option. The default code type is hex.

ascii: Specifies the code type for the remote ID sub-option as ascii.

hex: Specifies the code type for the remote ID sub-option as hex.

Usage guidelines

DHCP snooping uses ASCII to pad the specified string or system name for the remote ID sub-option. The code type for the normal padding format is determined by this command.

If you use this command multiple times, the most recent configuration takes effect.

Examples

# Pad the remote ID sub-option with the character string device001.

<Sysname> system-view

[Sysname] interface vlan-interface 10

[Sysname-Vlan-interface10] dhcp snooping information enable

[Sysname-Vlan-interface10] dhcp snooping information strategy replace

[Sysname-Vlan-interface10] dhcp snooping information remote-id string device001

Related commands

· dhcp snooping information enable

· dhcp snooping information strategy

· display dhcp snooping information

dhcp snooping information strategy

Use dhcp snooping information strategy to configure the handling strategy for Option 82 in request messages.

Use undo dhcp snooping information strategy to restore the default.

Syntax

dhcp snooping information strategy { drop | keep | replace }

undo dhcp snooping information strategy

Default

The handling strategy for Option 82 in request messages is replace.

Views

Layer 2 Ethernet interface view, Layer 2 aggregate interface view

Predefined user roles

network-admin

mdc-admin

Parameters

drop: Drops messages containing Option 82.

keep: Does not change Option 82.

replace: Replaces the original Option 82 with the configured Option 82.

Usage guidelines

This command takes effect only for DHCP request messages containing Option 82.

After you enable DHCP snooping to support Option 82, DHCP snooping always adds Option 82 in received request messages that do not contain Option 82 before forwarding the messages to the DHCP server.

Examples

# Configure the handling strategy for Option 82 in request messages as keep.

<Sysname> system-view

[Sysname] interface GigabitEthernet 3/0/1

[Sysname-GigabitEthernet3/0/1] dhcp snooping information enable

[Sysname-GigabitEthernet3/0/1] dhcp snooping information strategy keep

Related commands

· dhcp snooping information circuit-id

· dhcp snooping information remote-id

dhcp snooping trust

Use dhcp snooping trust to configure a port as a trusted port.

Use undo dhcp snooping trust to restore the default state of a port.

Syntax

dhcp snooping trust

undo dhcp snooping trust

Default

After you enable DHCP snooping, all ports are untrusted.

Views

Layer 2 Ethernet interface view, Layer 2 aggregate interface view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

Specify the ports facing the DHCP server as trusted ports and specify the other ports as untrusted ports so DHCP clients can obtain valid IP addresses.

Examples

# Specify the Layer 2 Ethernet interface GigabitEthernet 3/0/1 as a trusted port.

<Sysname> system-view

[Sysname] interface GigabitEthernet 3/0/1

[Sysname-GigabitEthernet3/0/1] dhcp snooping trust

Related commands

display dhcp snooping trust

display dhcp snooping binding

Use display dhcp snooping binding to display DHCP snooping entries.

Syntax

display dhcp snooping binding [ ip ip-address [ vlan vlan-id ] ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

ip ip-address: Displays the DHCP snooping entry for the specified IP address.

vlan vlan-id: Specifies the VLAN ID where the IP address resides.

Examples

# Display all DHCP snooping entries.

<Sysname> display dhcp snooping binding

5 DHCP snooping entries found

IP Address MAC Address Lease VLAN SVLAN Interface

=============== ============== ============ ===== ===== =================

1.1.1.1 0000-0101-0101 16907527 2 3 BAGG1023

1.1.1.2 0000-0101-0102 16907528 2 3 BAGG1023

1.1.1.4 0000-0101-0104 16907530 2 3 BAGG1023

1.1.1.7 0000-0101-0107 16907533 2 3 BAGG1023

1.1.1.11 0000-0101-010b 16907537 2 3 BAGG1023

Table 10 Command output

Field	Description
DHCP snooping entries found	Number of DHCP snooping entries.
IP Address	IP address assigned to the DHCP client.
MAC Address	MAC address of the DHCP client.
Lease	Remaining lease duration (in seconds).
VLAN	When both DHCP snooping and QinQ are enabled or the DHCP packet contains two VLAN tags, this field identifies the outer VLAN tag. Otherwise, it identifies the VLAN where the port connecting the DHCP client resides.
SVLAN	When both DHCP snooping and QinQ are enabled or the DHCP packet contains two VLAN tags, this field identifies the inner VLAN tag. Otherwise, it displays N/A.
Interface	Port connected to the DHCP client.

Related commands

· dhcp snooping enable

· reset dhcp snooping binding

display dhcp snooping binding database

Use display dhcp snooping binding database to display information about the file that stores DHCP snooping entries.

Syntax

display dhcp snooping binding database

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Examples

# Display information about the file that stores DHCP snooping entries.

<Sysname> display dhcp snooping binding database

File name : database.dhcp

Update interval : 600 seconds

Latest write time : Feb 27 18:48:04 2012

Status : Last write succeeded.

Table 11 Command output

Field	Description
File name	File name.
Update interval	Interval at which DHCP snooping entries are updated, in seconds.
Latest write time	Last time the file was written.
Status	Indicates whether the file was written successfully last time: · Writing—The file is being written. · Last write succeeded.—The file was written successfully. · Last write failed.—The file was not written successfully.

display dhcp snooping information

Use display dhcp snooping information to display Option 82 configuration on the DHCP snooping device.

Syntax

display dhcp snooping information { all | interface interface-type interface-number }

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

all: Displays Option 82 configuration on all Layer 2 Ethernet interfaces.

interface interface-type interface-number: Specifies an interface by its type and number.

Examples

# Display Option 82 configuration on all interfaces.

<Sysname> display dhcp snooping information all

Interface: Bridge-Aggregation1

Status: Disable

Strategy: Drop

Circuit ID:

Padding format: User Defined

User defined: abcd

Format: ASCII

Remote ID:

Padding format: Normal

Format: ASCII

VLAN 10:

Circuit ID: abcd

Remote ID: H3C

Table 12 Command output

Field	Description
Interface	Interface name.
Status	Option 82 status: Enable or Disable.
Strategy	Handling strategy for DHCP requests containing Option 82, Drop, Keep, or Replace.
Circuit ID	Content of the Circuit ID sub-option.
Padding format	Padding format of Option 82: · For circuit ID sub-option, the padding format can be Normal, User Defined, Verbose (sysname), Verbose (MAC), or Verbose (user defined). · For remote ID sub-option, the padding format can be Normal, Sysname, or User Defined.
Node identifier	Access node identifier.
User defined	Content of the user-defined sub-option.
Format	Code type of Option 82 sub-option: · For circuit ID sub-option, the code type can be ASCII, Default, or Hex. · For remote ID sub-option, the code type can be ASCII or Hex.
Remote ID	Content of the remote ID sub-option.
VLAN	Pads circuit ID sub-option and remote ID sub-option in the DHCP packets received in the specified VLAN.

display dhcp snooping packet statistics

Use display dhcp snooping packet statistics to display DHCP packet statistics for DHCP snooping.

Syntax

In standalone mode:

display dhcp snooping packet statistics [ slot slot-number ]

In IRF mode:

display dhcp snooping packet statistics [ chassis chassis-number slot slot-number ]

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Parameters

slot slot-number: Specifies a card by the slot number. (In standalone mode.)

chassis chassis-number slot slot-number: Specifies a card on an IRF member device. The chassis-number argument specifies the ID of the IRF member device. The slot-number argument specifies the number of the slot where the card resides. (In IRF mode.)

Usage guidelines

Without slot slot-number, this command displays DHCP packet statistics for the card where the command is executed. (In standalone mode.)

Without chassis chassis-number slot slot-number, this command displays DHCP packet statistics for the card of the member device where the command is executed. (In IRF mode.)

Examples

# Display DHCP packet statistics for DHCP snooping.

<Sysname> display dhcp snooping packet statistics

DHCP packets received : 100

DHCP packets sent : 200

Dropped invalid packets : 0

Related commands

reset dhcp snooping packet statistics

display dhcp snooping trust

Use display dhcp snooping trust to display information about trusted ports.

Syntax

display dhcp snooping trust

Views

Any view

Predefined user roles

network-admin

network-operator

mdc-admin

mdc-operator

Examples

# Display information about trusted ports.

<Sysname> display dhcp snooping trust

DHCP snooping is enabled.

DHCP snooping trust becomes active.

Interface Trusted

========================= ============

GigabitEthernet3/0/1 Trusted

Related commands

dhcp snooping trust

reset dhcp snooping binding

Use reset dhcp snooping binding to clear DHCP snooping entries.

Syntax

reset dhcp snooping binding { all | ip ip-address [ vlan vlan-id ] }

Views

User view

Predefined user roles

network-admin

mdc-admin

Parameters

all: Clears all DHCP snooping entries.

ip ip-address: Clears the DHCP snooping entry for the specified IP address.

vlan vlan-id: Clears DHCP snooping entries for the specified VLAN.

Usage guidelines

This command clears the specified DHCP snooping entries for all slots.

Examples

# Clear all DHCP snooping entries.

<Sysname> reset dhcp snooping binding all

Related commands

display dhcp snooping binding

reset dhcp snooping packet statistics

Use reset dhcp snooping packet statistics to clear DHCP packet statistics for DHCP snooping.

Syntax

In standalone mode:

reset dhcp snooping packet statistics [ slot slot-number ]

In IRF mode:

reset dhcp snooping packet statistics [ chassis chassis-number slot slot-number ]

Views

User view

Predefined user roles

network-admin

mdc-admin

Parameters

slot slot-number: Specifies a card by the slot number. (In standalone mode.)

chassis chassis-number slot slot-number: Specifies a card on an IRF member device. The chassis-number argument refers to the ID of the IRF member device. The slot-number argument specifies the number of the slot where the card resides. (In IRF mode.)

Usage guidelines

Without slot slot-number, this command clears DHCP packet statistics for the card where the command is executed. (In standalone mode.)

Without chassis chassis-number slot slot-number, this command clears DHCP packet statistics for the member device's card where the command is executed. (In IRF mode.)

Examples

# Clear DHCP packet statistics for DHCP snooping.

<Sysname> reset dhcp snooping packet statistics

Related commands

display dhcp snooping packet statistics

05-Layer 3 - IP Services Command Reference

DHCP commands

dhcp server apply ip-pool

dhcp server forbidden-ip

dhcp server ping packets

DHCP relay agent commands

dhcp relay check mac-address

dhcp relay client-information record

dhcp relay client-information refresh enable

dhcp relay information strategy

dhcp relay server-address

display dhcp relay client-information

display dhcp relay server-address

display dhcp relay statistics

reset dhcp relay client-information

dhcp snooping binding database update interval

display dhcp snooping binding

display dhcp snooping information

reset dhcp snooping binding

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