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13-DNS commands

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DNS commands

display dns domain

Use display dns domain to display the domain name suffixes.

Syntax

display dns domain [ dynamic ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

dynamic: Displays the domain name suffixes dynamically obtained through DHCP or other protocols. If you do not specify this keyword, the command displays the statically configured and dynamically obtained domain name suffixes.

Examples

# Display the statically configured and dynamically obtained domain name suffixes for the public network.

<Sysname> display dns domain

Type:

D: Dynamic S: Static

No. Type Domain suffix

1 S com

2 D net

Table 1 Command output

Field	Description
No.	Sequence number.
Type	Domain name suffix type: · S—A statically configured domain name suffix. · D—A domain name suffix dynamically obtained through DHCP or other protocols. ‌
Domain suffix	Domain name suffixes.

Related commands

dns domain

display dns host

Use display dns host to display information about domain name-to-IP address mappings.

Syntax

display dns host [ ip | ipv6 ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

ip: Specifies type A queries. A type A query resolves a domain name to the mapped IPv4 address.

ipv6: Specifies type AAAA queries. A type AAAA query resolves a domain name to the mapped IPv6 address.

Usage guidelines

If you do not specify the ip or ipv6 keyword, this command displays domain name-to-IP address mappings of both query types.

Examples

# Display domain name-to-IP address mappings of both query types.

<Sysname> display dns host

Type:

D: Dynamic S: Static

Total number: 3

No. Host name Interface Type TTL QType IP Count IP addresses

1 sample.com D 3132 A 3 192.168.10.1

192.168.10.2

192.168.10.3

2 zig.sample.com S - A 1 192.168.1.1

3 sample.net S - AAAA 1 FE80::4904:4448

Table 2 Command output

Field	Description
No.	Sequence number.
Host name	Domain name.
Interface	Name of the output interface.
Type	Domain name-to-IP address mapping type: · S—A static mapping configured by the ip host or ipv6 host command. · D—A mapping dynamically obtained through dynamic domain name resolution. ‌
TTL	Time in seconds that a mapping can be stored in the cache. For a static mapping, a hyphen (-) is displayed.
Query type	Query type: A and AAAA.
IP Count	Number of IP addresses corresponding to the domain name.
IP addresses	Replied IP addresses: · For a type A query, the replied IP addresses are IPv4 addresses. · For a type AAAA query, the replied IP addresses are IPv6 addresses.

Related commands

ip host

ipv6 host

reset dns host

display dns server

Use display dns server to display IPv4 DNS server information.

Syntax

display dns server [ dynamic ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

dynamic: Displays IPv4 DNS server information dynamically obtained through DHCP or other protocols. If you do not specify this keyword, the command displays statically configured and dynamically obtained IPv4 DNS server information.

Examples

# Display IPv4 DNS server information for the public network.

<Sysname> display dns server

Type:

D: Dynamic S: Static

No. Type IP address

1 S 202.114.0.124

2 S 169.254.65.125

Table 3 Command output

Field	Description
No.	Sequence number.
Type	DNS server type: · S—A manually configured DNS server. · D—DNS server information dynamically obtained through DHCP or other protocols. ‌
IP address	IPv4 address of the DNS server.

Related commands

dns server

display dns snooping host

Use display dns snooping host to display domain name-to-IP address mappings recorded by DNS snooping.

Syntax

display dns snooping host [ ip | ipv6 ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

ip: Specifies type A queries. A type A query resolves a domain name to the mapped IPv4 address.

ipv6: Specifies type AAAA queries. A type AAAA query resolves a domain name to the mapped IPv6 address.

Usage guidelines

If you do not specify the ip or ipv6 keyword, this command displays domain name-to-IP address mappings of both query types recorded by DNS snooping.

Examples

# Display domain name-to-IP address mappings of both query types recorded by DNS snooping.

<Sysname> display dns snooping host

Total number: 5

No. Host name Server TTL QType IP count IP addresses

1 a.example.com 8.8.8.8 3593 A 1 100.100.0.7

2 b.example.com 8.8.8.8 3595 A 2 100.100.0.8

100.100.0.9

3 c.example.com 8.8.8.8 3593 A 1 100.100.0.6

4 d.example.com 8.8.8.8 3597 AAAA 1 101:101::104

5 e.example.com 8.8.8.8 3597 AAAA 1 101:101::103

Table 4 Command output

Field	Description
No.	Sequence number.
Host name	Domain name.
Server	IP address of the DNS server.
TTL	Time in seconds that a mapping can be stored in the cache.
Qtype	Query type: A and AAAA.
IP count	Number of IP addresses corresponding to the domain name.
IP addresses	Replied IP addresses: · For a type A query, the replied IP addresses are IPv4 addresses. · For a type AAAA query, the replied IP addresses are IPv6 addresses.

Related commands

reset dns host

display ipv6 dns server

Use display ipv6 dns server to display IPv6 DNS server information.

Syntax

display ipv6 dns server [ dynamic ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

dynamic: Displays IPv6 DNS server information dynamically obtained through DHCP or other protocols. If you do not specify this keyword, the command displays the statically configured and dynamically obtained IPv6 DNS server information.

Examples

# Display IPv6 DNS server information for the public network.

<Sysname> display ipv6 dns server

Type:

D: Dynamic S: Static

No. Type IPv6 address Outgoing Interface

1 S 2::2

Table 5 Command output

Field	Description
No.	Sequence number.
Type	DNS server type: · S—A manually configured DNS server. · D—DNS server information dynamically obtained through DHCP or other protocols. ‌
IPv6 address	IPv6 address of the DNS server.
Outgoing Interface	Output interface.

Related commands

ipv6 dns server

dns cache ttl

Use dns cache ttl to set the TTL value for DNS entries.

Use undo dns cache ttl to cancel the TTL configuration for DNS entries.

Syntax

dns cache ttl { maximum max-value | minimum min-value } *

undo dns cache ttl [ maximum | minimum ]

Default

The TTL value for DNS entries is the TTL value in the DNS reply.

Views

System view

Predefined user roles

network-admin

Parameters

maximum max-value: Specifies the maximum TTL value for DNS entries, in the range of 60 to 3600 seconds.

minimum min-value: Specifies the minimum TTL value for DNS entries, in the range of 60 to 3600 seconds. The value for the min-value argument must be smaller than that for the max-value argument.

Usage guidelines

The device periodically sends a DNS request to the DNS server according to the TTL for DNS entries, which consumes CPU resources. If the TTL value is too small, the device sends DNS requests frequently to the DNS server, which consumes more CPU resources. If the TTL value is too large, DNS mappings cannot be updated in time. To avoid such issues, you can use this command to set the TTL value for DNS entries.

By default, the DNS client obtains the TTL for the following DNS entries from the DNS reply:

· DNS entries generated from DNS snooping.

· Dynamic domain name resolution cache generated from the DNS server/DNS server group.

After you set the TTL value for DNS entries, the device specifies the TTL for DNS entries as follows:

· If the TTL value in the DNS reply is smaller than the minimum TTL value, the device uses the minimum TTL value as the TTL for DNS entries. If the TTL value is greater than or equal to the minimum TTL value, the device uses the TTL value in the DNS reply as the TTL for DNS entries.

· If the TTL value in the DNS reply is greater than the maximum TTL value, the device uses the maximum TTL value as the TTL for DNS entries. If the TTL value is smaller than or equal to the maximum TTL value, the device uses the TTL value in the DNS reply as the TTL for DNS entries.

After you execute this command, the configuration only takes effect on the subsequent DNS entries generated from DNS snooping, and DNS server/DNS server group.

After you execute the undo dns cache ttl command, the current TTL for the existing DNS entries still works.

If you do not specify any keywords when you execute the undo dns cache ttl command, this command cancels all TTL configuration for DNS entries.

If you execute the dns cache ttl minimum, dns cache ttl maximum, or dns cache ttl minimum maximum command multiple times, the most recent configuration takes effect.

Examples

# Set the maximum TTL value for DNS entries to 3600 seconds and the minimum TTL value for DNS entries to 180 seconds.

<Sysname> system-view

[Sysname] dns cache ttl maximum 3600 minimum 180

Related commands

dns server

dns server-group

dns snooping enable

dns domain

Use dns domain to configure a domain name suffix.

Use undo dns domain to delete the specified domain name suffix.

Syntax

dns domain domain-name

undo dns domain domain-name

Default

No domain name suffix is configured. Only the provided domain name is resolved.

Views

System view

Predefined user roles

network-admin

Parameters

domain-name: Specifies a domain name suffix. It is a dot-separated, case-insensitive string that can include letters, digits, hyphens (-), underscores (_), and dots (.), for example, example.com. The domain name suffix can include a maximum of 253 characters, and each separated string includes no more than 63 characters.

Usage guidelines

For domain name resolution, the resolver automatically uses the suffix list to supply the missing part of an incomplete name entered by a user.

A domain name suffix applies to both IPv4 DNS and IPv6 DNS.

The system allows a maximum of 16 domain name suffixes for the public network.

Examples

# Configure domain name suffix com for the public network.

<Sysname> system-view

[Sysname] dns domain com

Related commands

display dns domain

dns dscp

Use dns dscp to set the DSCP value for DNS packets sent by a DNS client or DNS proxy.

Use undo dns dscp to restore the default.

Syntax

dns dscp dscp-value

undo dns dscp

Default

The DSCP value is 0 in DNS packets sent by a DNS client or DNS proxy.

Views

System view

Predefined user roles

network-admin

Parameters

dscp-value: Specifies the DSCP value in the range of 0 to 63.

Usage guidelines

The DSCP value of a packet specifies the priority level of the packet and affects the transmission priority of the packet. A bigger DSCP value represents a higher priority.

Examples

# Set the DSCP value to 30 for outgoing DNS packets.

<Sysname> system-view

[Sysname] dns dscp 30

dns fast-reply enable

Use dns fast-reply enable to enable DNS fast-reply.

Use undo dns fast-reply enable to disable DNS fast-reply.

Syntax

dns fast-reply enable

undo dns fast-reply enable

Default

DNS fast-reply is disabled.

Views

System view

AP group view

Predefined user roles

network-admin

Usage guidelines

As DNS fast-reply can process a large number of DNS requests per second, use this feature in scenarios that require high DNS packet processing performance.

With this feature enabled, the device monitors the received DNS requests (only UDP packets are supported in the current software version). Then, it resolves the domain names in the requests, and searches for a match in the local static domain name resolution table.

· If a match is found, the device sends a DNS reply to the DNS client.

· If no match is found, the device forwards the query to the DNS server.

This command enables both IPv4 DNS fast-reply and IPv6 DNS fast-reply.

After you enable DNS fast-reply in AP group view on an AC, the configuration is deployed to the APs in the AP group. As a result, DNS fast-reply is also enabled on the APs.

Examples

# Enable DNS fast-reply (in system view).

<Sysname> system-view

[Sysname] dns fast-reply enable

# Enable DNS fast-reply (in AP group view).

<Sysname> system-view

[Sysname] wlan ap-group group1

[Sysname-wlan-ap-group-group1] dns fast-reply enable

Related commands

dns transparent-proxy enable

dns proxy enable

Use dns proxy enable to enable DNS proxy.

Use undo dns proxy enable to disable DNS proxy.

Syntax

dns proxy enable

undo dns proxy enable

Default

DNS proxy is disabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

This configuration applies to both IPv4 DNS and IPv6 DNS.

Examples

# Enable DNS proxy.

<Sysname> system-view

[Sysname] dns proxy enable

dns server

Use dns server to specify the IPv4 address of a DNS server.

Use undo dns server to remove the IPv4 address of a DNS server.

Syntax

dns server ip-address

undo dns server [ ip-address ]

Default

No DNS server IPv4 address is specified.

Views

System view

Interface view

Predefined user roles

network-admin

Parameters

ip-address: Specifies the IPv4 address of a DNS server. When you execute the undo form of the command in interface view, you must specify this argument.

Usage guidelines

The system allows a maximum of six DNS server IPv4 addresses for the public network.

If you do not specify an IPv4 address, the undo dns server command removes all DNS server IPv4 addresses for the public network.

Examples

# Specify DNS server IPv4 address 172.16.1.1.

<Sysname> system-view

[Sysname] dns server 172.16.1.1

# Specify DNS server IPv4 address 172.16.1.1 on VLAN-interface 2. ‌

<Sysname> system-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] dns server 172.16.1.1

Related commands

display dns server

dns snooping enable

Use dns snooping enable to enable DNS snooping.

Use undo dns snooping enable to disable DNS snooping.

Syntax

dns snooping enable

undo dns snooping enable

Default

DNS snooping is disabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

DNS snooping is applicable to scenarios that use domain name-based policies (such as security policies and bandwidth policies). In such a scenario, the device requires the resolved IP addresses for traffic filtering. Enabled with DNS snooping, the device monitors received DNS requests and replies, and works as follows:

· If the domain name in a DNS request matches a policy, the device records the DNS mapping after receiving the DNS reply, and reports the mapping to the policy for traffic filtering.

· If the domain name does not match a policy, the device does not record the DNS mapping.

DNS snooping works only between the DNS client and DNS server, or the DNS client and DNS proxy.

Examples

# Enable DNS snooping.

<Sysname> system-view

[Sysname] dns snooping enable

dns snooping log enable

Use dns snooping log enable to enable DNS snooping logging.

Use undo dns snooping log enable to disable DNS snooping logging.

Syntax

dns snooping log enable

undo dns snooping log enable

Default

DNS snooping logging is disabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

The DNS proxy searches the static domain name resolution table and dynamic domain name resolution cache after receiving a request.

· If the requested information is found, the DNS proxy returns a DNS reply to the client.

· If the requested information is not found, the DNS proxy sends the request to the designated DNS server.

Too many requests received at the same time will increase network load and affect the performance of the DNS proxy and DNS server.

To avoid this issue, you can configure DNS snooping on the device between the DNS client and DNS proxy, or the DNS client and DNS server. Also, you can configure the device to generate and send DNS snooping logs to the fast log module. The administrator can locate and troubleshoot issues based on the logs. For information about the fast log output function, see Network Management and Monitoring Configuration Guide.

Examples

# Enable DNS snooping logging.

<Sysname> system-view

[Sysname] dns snooping log enable

dns source-interface

Use dns source-interface to specify the source interface for DNS packets.

Use undo dns source-interface to restore the default.

Syntax

dns source-interface interface-type interface-number

undo dns source-interface interface-type interface-number

Default

No source interface is specified for DNS packets. The device uses the primary IP address of the output interface of the matching route as the source IP address for a DNS request.

Views

System view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

This configuration applies to both IPv4 and IPv6.

In IPv4 DNS, the device uses the primary IPv4 address of the specified source interface as the source IP address of a DNS query. In IPv6 DNS, the device selects an IPv6 address of the specified source interface as the source IP address of a DNS query. The method of selecting the IPv6 address is defined in RFC 3484.

The system allows only one source interface for the public network. If you execute this command multiple times, the most recent configuration takes effect.

Examples

# Specify VLAN-interface 2 as the source interface for DNS packets on the public network. ‌

<Sysname> system-view

[Sysname] dns source-interface vlan-interface 2

dns spoofing

Use dns spoofing to enable DNS spoofing and specify the IPv4 address for spoofing DNS requests.

Use undo dns spoofing to disable DNS spoofing.

Syntax

dns spoofing ip-address

undo dns spoofing ip-address

Default

DNS spoofing is disabled.

Views

System view

Predefined user roles

network-admin

Parameters

ip-address: Specifies the IPv4 address used to spoof DNS requests.

Usage guidelines

Use the dns spoofing command together with the dns proxy enable command.

DNS spoofing functions when the DNS proxy does not know the DNS server address or cannot reach the DNS server. It enables the DNS proxy to spoof DNS queries of type A by responding with the specified IPv4 address.

The system allows only one replied IPv4 address for the public network. If you execute this command multiple times, the most recent configuration takes effect.

Examples

# Enable DNS spoofing for the public network and specify IPv4 address 1.1.1.1 for spoofing DNS requests.

<Sysname> system-view

[Sysname] dns proxy enable

[Sysname] dns spoofing 1.1.1.1

Related commands

dns proxy enable

dns trust-interface

Use dns trust-interface to specify a DNS trusted interface.

Use undo dns trust-interface to remove a DNS trusted interface.

Syntax

dns trust-interface interface-type interface-number

undo dns trust-interface [ interface-type interface-number ]

Default

No DNS trusted interface is specified.

Views

System view

Predefined user roles

network-admin

Parameters

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

Usage guidelines

By default, an interface obtains DNS suffix and DNS server information from DHCP. A network attacker might act as the DHCP server to assign a wrong DNS suffix and DNS server address to the device. As a result, the device fails to obtain the resolved IP address or might get the wrong IP address. With the DNS trusted interface specified, the device only uses the DNS suffix and DNS server information obtained through the trusted interface to avoid attacks.

This configuration applies to both IPv4 DNS and IPv6 DNS.

You can configure a maximum of 128 DNS trusted interfaces on the device.

If you do not specify an interface, the undo dns trust-interface command removes all DNS trusted interfaces and restores the default.

Examples

# Specify VLAN-interface 2 as a DNS trusted interface. ‌

<Sysname> system-view

[Sysname] dns trust-interface vlan-interface 2

ip host

Use ip host to create a host name-to-IPv4 address mapping.

Use undo ip host to remove a host name-to-IPv4 address mapping.

Syntax

ip host host-name ip-address

undo ip host host-name ip-address

Default

No host name-to-IPv4 address mappings exist.

Views

System view

AP group view

Predefined user roles

network-admin

Parameters

host-name: Specifies a host name, a case-insensitive string of 1 to 253 characters that can contain letters, digits, hyphens (-), underscores (_), and dots (.). A host name must meet the following requirements:

· The host name string is separated by dots (.). Each separated part includes up to 63 characters.

· The host name cannot start or end with a dot (.).

· The host name cannot contain two consecutive dots (..).

ip-address: Specifies the IPv4 address of the host.

Usage guidelines

The system allows a maximum of 1024 host name-to-IPv4 address mappings for the public network.

For the public network, each host name maps to only one IPv4 address. If you execute this command multiple times, the most recent configuration takes effect.

Do not use the ping command parameter ip, -a, -c, -f, -h, -i, -m, -n, -p, -q, -r, -s, -t, -tos, -v, or -vpn-instance as the host name. For more information about the ping command parameters, see Network Management and Monitoring Command Reference.

After you create a host name-to-IPv4 address mapping in AP group view on an AC, the configuration is deployed to the APs in the AP group. As a result, the mapping is also created on the APs.

Examples

# Map IPv4 address 10.110.0.1 to host name aaa for the public network (in system view).

<Sysname> system-view

[Sysname] ip host aaa 10.110.0.1

# Map IPv4 address 10.110.0.1 to host name aaa for the public network (in AP group view).

<Sysname> system-view

[Sysname] wlan ap-group group1

[Sysname-wlan-ap-group-group1] ip host aaa 10.110.0.1

Related commands

display dns host

ipv6 dns dscp

Use ipv6 dns dscp to set the DSCP value for IPv6 DNS packets sent by an IPv6 DNS client or IPv6 DNS proxy.

Use undo ipv6 dns dscp to restore the default.

Syntax

ipv6 dns dscp dscp-value

undo ipv6 dns dscp

Default

The DSCP value is 0 in IPv6 DNS packets sent by an IPv6 DNS client or IPv6 DNS proxy.

Views

System view

Predefined user roles

network-admin

Parameters

dscp-value: Specifies the DSCP value in the range of 0 to 63.

Usage guidelines

The DSCP value of a packet specifies the priority level of the packet and affects the transmission priority of the packet. A bigger DSCP value represents a higher priority.

Examples

# Set the DSCP value to 30 for outgoing IPv6 DNS packets.

<Sysname> system-view

[Sysname] ipv6 dns dscp 30

ipv6 dns server

Use ipv6 dns server to specify the IPv6 address of a DNS server.

Use undo ipv6 dns server to remove the IPv6 address of a DNS server.

Syntax

ipv6 dns server ipv6-address [ interface-type interface-number ]

undo ipv6 dns server [ ipv6-address [ interface-type interface-number ] ]

Default

No DNS server IPv6 address is specified.

Views

System view

Predefined user roles

network-admin

Parameters

ipv6-address: Specifies the IPv6 address of a DNS server.

interface-type interface-number: Specifies the output interface by its type and number. If you do not specify an interface, the device forwards DNS packets out of the output interface of the matching route. Specify this argument if the IPv6 address of the DNS server is a link-local address. Do not specify this argument if the IPv6 address of the DNS server is a global unicast address.

Usage guidelines

The system allows a maximum of six DNS server IPv6 addresses for the public network.

If you do not specify an IPv6 address, the undo ipv6 dns server command removes all DNS server IPv6 addresses for the public network.

Examples

# Specify DNS server IPv6 address 2002::1 for the public network.

<Sysname> system-view

[Sysname] ipv6 dns server 2002::1

Related commands

display ipv6 dns server

ipv6 dns spoofing

Use ipv6 dns spoofing to enable DNS spoofing and specify the IPv6 address to spoof DNS requests.

Use undo ipv6 dns spoofing to disable DNS spoofing.

Syntax

ipv6 dns spoofing ipv6-address

undo ipv6 dns spoofing ipv6-address

Default

DNS spoofing is disabled.

Views

System view

Predefined user roles

network-admin

Parameters

ipv6-address: Specifies the IPv6 address used to spoof DNS requests.

Usage guidelines

Use the ipv6 dns spoofing command together with the dns proxy enable command.

DNS spoofing functions when the DNS proxy does not know the DNS server address or cannot reach the DNS server. It enables the DNS proxy to spoof DNS queries of type AAAA by responding with the specified IPv6 address.

The system allows only one replied IPv6 address for the public network. If you execute this command multiple times, the most recent configuration takes effect.

Examples

# Enable DNS spoofing for the public network and specify IPv6 address 2001::1 for spoofing DNS requests.

<Sysname> system-view

[Sysname] dns proxy enable

[Sysname] ipv6 dns spoofing 2001::1

Related commands

dns proxy enable

ipv6 host

Use ipv6 host to create a host name-to-IPv6 address mapping.

Use undo ipv6 host to remove a host name-to-IPv6 address mapping.

Syntax

ipv6 host host-name ipv6-address

undo ipv6 host host-name ipv6-address

Default

No host name-to-IPv6 address mappings exist.

Views

System view

AP group view

Predefined user roles

network-admin

Parameters

· The host name string is separated by dots (.). Each separated part includes up to 63 characters.

· The host name cannot start or end with a dot (.).

· The host name cannot contain two consecutive dots (..).

ipv6-address: Specifies the IPv6 address of the host.

Usage guidelines

The system allows a maximum of 1024 host name-to-IPv6 address mappings for the public network.

For the public network, each host name maps to only one IPv6 address. If you execute this command multiple times, the most recent configuration takes effect.

Do not use the ping ipv6 command parameter -a, -c, -i, -m, -q, -s, -t, -tc, -v, or -vpn-instance as the host name. For more information about the ping ipv6 command parameters, see Network Management and Monitoring Command Reference.

After you create a host name-to-IPv6 address mapping in AP group view on an AC, the configuration is deployed to the APs in the AP group. As a result, the mapping is also created on the APs.

Examples

# Map IPv6 address 2001::1 to host name aaa for the public network (in system view).

<Sysname> system-view

[Sysname] ipv6 host aaa 2001::1

# Map IPv6 address 2001::1 to host name aaa for the public network (in AP group view).

<Sysname> system-view

[Sysname] wlan ap-group group1

[Sysname-wlan-ap-group-group1] ipv6 host aaa 2001::1

Related commands

ip host

reset dns host

Use reset dns host to clear dynamic DNS entries.

Syntax

reset dns host [ ip | ipv6 ]

Views

User view

Predefined user roles

network-admin

Parameters

ip: Specifies type A queries. A type A query resolves a domain name to the mapped IPv4 address.

ipv6: Specifies type AAAA queries. A type AAAA query resolves a domain name to the mapped IPv6 address.

Usage guidelines

If you do not specify the ip or ipv6 keyword, the reset dns host command clears dynamic DNS entries of both query types.

Use this command to clear the following dynamic DNS entries:

· Dynamic DNS entries on the DNS client.

· Dynamic DNS entries on the device enabled with DNS snooping.

Examples

# Clear dynamic DNS entries of all query types for the public network.

<Sysname> reset dns host

Related commands

display dns host

dns snooping enable

DDNS commands

ddns apply policy

Use ddns apply policy to apply a DDNS policy to an interface and enable DDNS update. DDNS updates the mapping between the FQDN and the primary IP address of the interface.

Use undo ddns apply policy to remove the application of a DDNS policy from an interface and to stop DDNS update.

Syntax

ddns apply policy policy-name [ fqdn domain-name ]

undo ddns apply policy policy-name

Default

No DDNS policy and FQDN are specified on the interface, and DDNS update is disabled.

Views

Interface view

Predefined user roles

network-admin

Parameters

policy-name: Specifies a DDNS policy by its name, a case-insensitive string of 1 to 32 characters.

fqdn domain-name: Specifies the FQDN to replace <h> in the URL for DDNS update. The domain-name argument specifies a case-insensitive string of 1 to 253 characters. It can include letters, digits, hyphens (-), underscores (_), and dots (.).

Usage guidelines

You can apply a maximum of four DDNS policies to an interface.

If you execute this command multiple times with the same DDNS policy name but different FQDNs, both of the following occur:

· The most recent configuration takes effect.

· The device initiates a DDNS update request immediately.

Examples

# Apply DDNS policy steven_policy to VLAN-interface 2 to update the domain name-to-IP address mapping for FQDN www.example.com and enable DDNS update. ‌

<Sysname> system-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] ddns apply policy steven_policy fqdn www.example.com

Related commands

ddns policy

display ddns policy

ddns dscp

Use ddns dscp to set the DSCP value for outgoing DDNS packets.

Use undo ddns dscp to restore the default.

Syntax

ddns dscp dscp-value

undo ddns dscp

Default

The DSCP value for outgoing DDNS packets is 0.

Views

System view

Predefined user roles

network-admin

Parameters

dscp-value: Specifies the DSCP value in the range of 0 to 63.

Usage guidelines

The DSCP value of a packet specifies the priority level of the packet and affects the transmission priority of the packet. A bigger DSCP value represents a higher priority.

Examples

# Set the DSCP value to 30 for outgoing DDNS packets.

<Sysname> system-view

[Sysname] ddns dscp 30

ddns policy

Use ddns policy to create a DDNS policy and enter its view, or enter the view of an existing DDNS policy.

Use undo ddns policy to delete a DDNS policy.

Syntax

ddns policy policy-name

undo ddns policy policy-name

Default

No DDNS policies exist.

Views

System view

Predefined user roles

network-admin

Parameters

policy-name: Specifies the DDNS policy name, a case-insensitive string of 1 to 32 characters.

Usage guidelines

You can create a maximum of 16 DDNS policies on the device.

Examples

# Create a DDNS policy named steven_policy and enter its view.

<Sysname> system-view

[Sysname] ddns policy steven_policy

Related commands

ddns apply policy

display ddns policy

Use display ddns policy to display information about DDNS policies.

Syntax

display ddns policy [ policy-name ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

policy-name: Specifies a DDNS policy by its name, a case-insensitive string of 1 to 32 characters. If you do not specify a DDNS policy, this command displays information about all DDNS policies.

Examples

# Display information about DDNS policy steven_policy.

<Sysname> display ddns policy steven_policy

DDNS policy: steven_policy

URL : http://members.3322.org/dyndns/update?

system=dyndns&hostname=<h>&myip=<a>

Username : steven

Password : ******

Method : GET

SSL client policy:

Interval : 1 days 0 hours 1 minutes

# Display information about all DDNS policies.

<Sysname> display ddns policy

DDNS policy: steven_policy

URL : http://members.3322.org/dyndns/update?system=

dyndns&hostname=<h>&myip=<a>

Username : steven

Password : ******

Method : GET

SSL client policy:

Interval : 0 days 0 hours 30 minutes

DDNS policy: tom-policy

URL : http://members.3322.org/dyndns/update?system=

dyndns&hostname=<h>&myip=<a>

Username :

Password :

Method : GET

SSL client policy:

Interval : 0 days 0 hours 15 minutes

DDNS policy: u-policy

URL : oray://phddns60.oray.net

Username : username

Password :

Method : -

SSL client policy:

Interval : 0 days 0 hours 15 minutes

Table 6 Command output

Field	Description
DDNS policy	DDNS policy name.
URL	URL address for a DDNS update request. This field is empty if no URL address is configured.
Username	Username for logging in to the DDNS server. This field is empty if no username is configured.
Password	Password for logging in to the DDNS server. This field is empty if no password is configured and displays ****** if a password is configured.
Method	Parameter transmission method used to send HTTP/HTTPS-based DDNS update requests. Method types include GET and POST.
SSL client policy	‌ Name of the associated SSL client policy. This field is empty if no SSL client policy is associated.
Interval	Interval for sending DDNS update requests.

Related commands

ddns policy

interval

Use interval to set the interval for sending DDNS update requests.

Use undo interval to restore the default.

Syntax

interval days [ hours [ minutes ] ]

undo interval

Default

The DDNS update request interval is 1 hour.

Views

DDNS policy view

Predefined user roles

network-admin

Parameters

days: Days in the range of 0 to 365.

hours: Hours in the range of 0 to 23.

minutes: Minutes in the range of 0 to 59.

Usage guidelines

The interface always sends a DDNS update request in one of the following conditions:

· The primary IP address of the interface changes.

· The link state of the interface changes from down to up.

If you set the interval to 0, the device does not periodically initiate DDNS update requests.

If you execute this command multiple times, the most recent configuration takes effect. If you change the interval for an applied DDNS policy, the device immediately initiates a DDNS update request and sets the interval as the update interval.

Examples

# Set the interval to 1 day and 1 minute for sending DDNS update requests for DDNS policy steven_policy.

<Sysname> system-view

[Sysname] ddns policy steven_policy

[Sysname-ddns-policy-steven_policy] interval 1 0 1

Related commands

ddns policy

display ddns policy

method

Use method to specify the parameter transmission method for sending DDNS update requests to HTTP/HTTPS-based DDNS servers.

Use undo method to restore the default.

Syntax

method { http-get | http-post }

undo method

Default

The method http-get applies.

Views

DDNS policy view

Predefined user roles

network-admin

Parameters

http-get: Uses the get operation.

http-post: Uses the post operation.

Usage guidelines

This command applies to DDNS updates in HTTP/HTTPS. If the DDNS server uses HTTP or HTTPS service, choose a parameter transmission method compatible with the DDNS server. For example, a DHS server supports the http-post method.

If the DDNS policy has been applied to an interface, a DDNS update is sent immediately after the parameter transmission is changed.

Examples

# Specify the parameter transmission method as http-post for DDNS update requests for DDNS policy steven_policy.

<Sysname> system-view

[Sysname] ddns policy steven_policy

[Sysname-ddns-policy-steven_policy] method http-post

Related commands

ddns policy

display ddns policy

password

Use password to specify the password for logging in to the DDNS server.

Use undo password to restore the default.

Syntax

password { cipher | simple } string

undo password

Default

No password is specified for logging in to the DDNS server.

Views

DDNS policy view

Predefined user roles

network-admin

Parameters

cipher: Specifies a password in encrypted form.

simple: Specifies a password in plaintext form. For security purposes, the password specified in plaintext form will be stored in encrypted form.

string: Specifies the password. Its plaintext form is a case-sensitive string of 1 to 32 characters. Its encrypted form is a case-sensitive string of 1 to 73 characters.

Examples

# In DDNS policy steven_policy, specify nevets as the password for logging in to the DDNS server.

<Sysname> system-view

[Sysname] ddns policy steven_policy

[Sysname-ddns-policy-steven_policy] password simple nevets

Related commands

ddns policy

display ddns policy

url

username

ssl-client-policy

Use ssl-client-policy to associate an SSL client policy with a DDNS policy.

Use undo ssl-client-policy to restore the default.

Syntax

ssl-client-policy policy-name

undo ssl-client-policy

Default

No SSL client policy is associated with a DDNS policy.

Views

DDNS policy view

Predefined user roles

network-admin

Parameters

policy-name: Specifies a SSL client policy by its name, a case-insensitive string of 1 to 255 characters.

Usage guidelines

The SSL client policy is effective only for HTTPS-based DDNS update requests.

If you execute this command multiple times with different SSL client policies, the most recent configuration takes effect.

Examples

# Associate SSL client policy ssl_policy with DDNS policy steven_policy.

<Sysname> system-view

[Sysname] ddns policy steven_policy

[Sysname-ddns-policy-steven_policy] ssl-client-policy ssl_policy

Related commands

ddns policy

display ddns policy

ssl-client-policy (Security Command Reference)

url

Use url to specify the URL address for DDNS update requests.

Use undo url to restore the default.

Syntax

url request-url

undo url

Default

No URL address is specified for DDNS update requests.

Views

DDNS policy view

Predefined user roles

network-admin

Parameters

request-url: Specifies the URL address, a case-sensitive string of 1 to 240 characters.

Usage guidelines

The URL addresses configured for update requests vary by DDNS server. Common DDNS server URL address formats are shown in Table 7.

Table 7 Common URL addresses for DDNS update request

DDNS server	URL addresses for DDNS update requests
www.3322.org	http://members.3322.org/dyndns/update?system=dyndns&hostname=<h>&myip=<a>
DYNDNS	http://members.dyndns.org/nic/update?system=dyndns&hostname=<h>&myip=<a>
DYNS	http://www.dyns.cx/postscript.php?host=<h>&ip=<a>
ZONEEDIT	http://dynamic.zoneedit.com/auth/dynamic.html?host=<h>&dnsto=<a>
TZO	http://cgi.tzo.com/webclient/signedon.html?TZOName=<h>IPAddress=<a>
EASYDNS	http://members.easydns.com/dyn/ez-ipupdate.php?action=edit&myip=<a>&host_id=<h>
HEIPV6TB	http://dyn.dns.he.net/nic/update?hostname=<h>&myip=<a>
CHANGE-IP	http://nic.changeip.com/nic/update?hostname=<h>&offline=1
NO-IP	http://dynupdate.no-ip.com/nic/update?hostname=<h>&myip=<a> Do not specify the myip parameter if traffic from the DDNS client to the DDNS server goes through a NAT device.
DHS	http://members.dhs.org/nic/hosts?domain=dyn.dhs.org&hostname=<h>&hostscmd=edit&hostscmdstage=2&type=1&ip=<a>
HP	https://server-name/nic/update?group=group-name&myip=<a>
ODS	ods://update.ods.org
GNUDIP	gnudip://server-name
PeanutHull	· oray://phddns60.oray.net · oray://phservice2.oray.net · http://ddns.oray.com/ph/update?hostname=<h>&myip=<a>

The URL address cannot contain the username or password. To configure the username and password, use the username command and the password command.

HP and GNUDIP are common DDNS update protocols. The server-name parameter is the domain name or IP address of the service provider's server using one of the update protocols.

The URL address for an update request can start with:

· http://—The HTTP-based DDNS server.

· https://—The HTTPS-based DDNS server.

· ods://—The TCP-based ODS server.

· gnudip://—The TCP-based GNUDIP server.

· oray://—The TCP-based DDNS server.

The domain names of DDNS servers are members.3322.org and phddns60.oray.net. The domain names of PeanutHull DDNS servers can be phddns60.oray.net and phservice2.oray.net. The domain name phservice2.oray.net maps to the public IP address of the old version PeanutHull DDNS server, which is not maintained any more. You need to try several times upon failures to connect to the server. As a best practice, register a new account and a domain name on the PeanutHull DDNS of a new version. Determine the domain name in the URL according to the actual situation.

The port number in the URL address is optional. If you do not specify a port number, the default port number is used. HTTP uses port 80, HTTPS uses port 443, and the PeanutHull server uses port 6060.

The system automatically performs the following tasks:

· Fills <h> with the FQDN that is specified when the DDNS policy is applied to an interface.

· Fills <a> with the primary IP address of the interface to which the DDNS policy is applied.

You can also manually specify an FQDN and an IP address in <h> and <a>, respectively. In this case, the FQDN that is specified when the DDNS policy is applied to an interface will not take effect. As a best practice, do not manually change the <h> and <a> because your configuration might be incorrect.

You cannot specify an FQDN and IP address in the URL address for contacting the PeanutHull server. Alternatively, you can specify an FQDN when applying the DDNS policy to an interface. The system automatically uses the primary IP address of the interface to which the DDNS policy is applied as the IP address for DDNS update.

To avoid misinterpretation, do not include colons (:), at signs (@), and question marks (?) in your login username or password, even if you can do so.

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

Examples

# Specify the URL address for DDNS update requests for DDNS policy steven_policy. The device contacts www.3322.org for DDNS update.

<Sysname> system-view

[Sysname] ddns policy steven_policy

[Sysname-ddns-policy-steven_policy] url http:// members.3322.org/dyndns/update?system=dyndns&hostname=<h>&myip=<a>

Related commands

ddns policy

display ddns policy

password

username

Use username to specify the username for logging in to the DDNS server.

Use undo username to restore the default.

Syntax

username username

undo username

Default

No username is specified for logging in to the DDNS server.

Views

DDNS policy view

Predefined user roles

network-admin

Parameters

username: Specifies the username, a case-sensitive string of 1 to 32 characters.

Examples

# In DDNS policy steven_policy, specify steven as the username for logging in to the DDNS server.

<Sysname> system-view

[Sysname] ddns policy steven_policy

[Sysname-ddns-policy-steven_policy] username steven

Related commands

ddns policy

display ddns policy

password

url

05-Network Connectivity Command Reference

display dns domain

display ipv6 dns server

dns proxy enable

dns server

DDNS commands

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