Contents

Configuring IP source guard· 1

About IPSG·· 1

IPSG operating mechanism·· 1

Static IPSG bindings· 1

Dynamic IPSG bindings· 1

IPSG tasks at a glance· 2

Configuring the IPv4SG feature· 2

Enabling IPv4SG on an interface· 2

Configuring a static IPv4SG binding· 3

Configuring the IPv6SG feature· 3

Enabling IPv6SG on an interface· 3

Configuring a static IPv6SG binding· 4

Display and maintenance commands for IPSG·· 4

IPSG configuration examples· 5

Example: Configuring static IPv4SG·· 5

Example: Configuring dynamic IPv4SG using DHCP relay agent 6

Example: Configuring static IPv6SG·· 7

Example: Configuring dynamic IPv6SG using DHCPv6 relay agent 7

 

Configuring IP source guard

About IPSG

IP source guard (IPSG) prevents spoofing attacks by using an IPSG binding table to filter out illegitimate packets. This feature is typically configured on user-side interfaces.

IPSG operating mechanism

The IPSG binding table contains bindings that bind IP address, MAC address, VLAN, or any combinations. IPSG uses the bindings to match an incoming packet. If a match is found, the packet is forwarded. If no match is found, the packet is discarded.

IPSG is a per-interface packet filter. Configuring this feature on one interface does not affect packet forwarding on another interface.

IPSG bindings can be static or dynamic.

As shown in Figure 1, IPSG forwards only the packets that match an IPSG binding.

Figure 1 IPSG application

 

 

Static IPSG bindings

Static IPSG bindings are configured manually. They are suitable for scenarios where few hosts exist on a LAN and their IP addresses are manually configured. For example, you can configure a static IPSG binding on an interface that connects to a server. This binding allows the interface to receive packets only from the server.

Static IPSG bindings on an interface filter incoming IPv4 or IPv6 packets on the interface.

Interface-specific static binding binds the IP address, MAC address, or any combination of the items in interface view. The binding takes effect only on the interface to check the validity of users who are attempting to access the interface.

Dynamic IPSG bindings

IPSG automatically obtains user information from other modules to generate dynamic bindings. A dynamic IPSG binding can contain MAC address, IPv4 or IPv6 address, VLAN tag, ingress interface, and binding type. The binding type identifies the source module for the binding, such as DHCPv4 relay agent or DHCPv6 relay agent.

For example, DHCP-based IPSG bindings are suitable for scenarios where hosts on a LAN obtain IP addresses through DHCP. IPSG is configured on the DHCP server or the DHCP relay agent. It generates dynamic bindings based on the client bindings on the DHCP server or the DHCP relay entries. IPSG allows only packets from the DHCP clients to pass through.

Dynamic IPv4SG

Dynamic bindings generated based on different source modules are for different usages:

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Interface types	Source modules	Binding usage
Layer 3 Ethernet interface VLAN interface	DHCP relay agent	Packet filtering.
	DHCP server	For cooperation with modules (such as the authorized ARP module) to provide security services.

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For information about DHCP relay and DHCP server, see Layer 3—IP Services Configuration Guide.

Dynamic IPv6SG

Dynamic IPv6SG bindings generated based on the following source modules are for packet filtering:

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Interface types	Source modules
Layer 3 Ethernet interface VLAN interface	DHCPv6 relay agent

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For more information about DHCPv6 relay agent, see Layer 3—IP Services Configuration Guide.

IPSG tasks at a glance

To configure IPv4SG, perform the following tasks:

1.     Enabling IPv4SG on an interface

2.     (Optional.) Configuring a static IPv4SG binding

To configure IPv6SG, perform the following tasks:

1.     Enabling IPv6SG on an interface

2.     (Optional.) Configuring a static IPv6SG binding

Configuring the IPv4SG feature

Enabling IPv4SG on an interface

About this task

When you enable IPSG on an interface, the static and dynamic IPSG are both enabled.

·     Static IPv4SG uses static bindings configured by using the ip source binding command. For more information, see "Configuring a static IPv4SG binding."

·     Dynamic IPv4SG generates dynamic bindings from related source modules. IPv4SG uses the bindings to filter incoming IPv4 packets based on the matching criteria specified in the ip verify source command.

Restrictions and guidelines

To implement dynamic IPv4SG, make sure DHCP relay agent or DHCP server operates correctly on the network.

Procedure

1.     Enter system view.

system-view

2.     Enter interface view.

interface interface-type interface-number

The following interface types are supported:

¡     Layer 3 Ethernet interface.

¡     Layer 3 Ethernet subinterface.

¡     Layer 3 aggregate interface.

¡     Layer 3 aggregate subinterface.

¡     VLAN interface.

3.     Enable the IPv4SG feature.

ip verify source  ip-address mac-address

By default, the IPv4SG feature is disabled on an interface.

Configuring a static IPv4SG binding

Configuring a static IPv4SG binding on an interface

1.     Enter system view.

system-view

2.     Enter interface view.

interface interface-type interface-number

The following interface types are supported:

¡     Layer 3 Ethernet interface.

¡     Layer 3 Ethernet subinterface.

¡     VLAN interface.

3.     Configure a static IPv4SG binding.

ip source binding ip-address ip-address mac-address mac-address

You can configure the same static IPv4SG binding on different interfaces.

Configuring the IPv6SG feature

Enabling IPv6SG on an interface

About this task

When you enable IPv6SG on an interface, the static and dynamic IPv6SG are both enabled.

·     Static IPv6SG uses static bindings configured by using the ipv6 source binding command. For more information, see "Configuring a static IPv6SG binding."

·     Dynamic IPv6SG generates dynamic bindings from related source modules. IPv6SG uses the bindings to filter incoming IPv6 packets based on the matching criteria specified in the ipv6 verify source command.

Restrictions and guidelines

To implement dynamic IPv6SG, make sure DHCPv6 relay agent operates correctly on the network.

Procedure

1.     Enter system view.

system-view

2.     Enter interface view.

interface interface-type interface-number

The following interface types are supported:

¡     Layer 3 Ethernet interface.

¡     Layer 3 Ethernet subinterface.

¡     Layer 3 aggregate interface.

¡     Layer 3 aggregate subinterface.

¡     VLAN interface.

3.     Enable the IPv6SG feature.

ipv6 verify source ip-address mac-address

By default, the IPv6SG feature is disabled on an interface.

Configuring a static IPv6SG binding

Configuring a static IPv6SG binding on an interface

1.     Enter system view.

system-view

2.     Enter interface view.

interface interface-type interface-number

The following interface types are supported:

¡     Layer 3 Ethernet interface.

¡     Layer 3 Ethernet subinterface.

¡     VLAN interface.

3.     Configure a static IPv6SG binding.

ipv6 source binding ip-address ipv6-address mac-address mac-address

You can configure the same static IPv6SG binding on different interfaces.

Display and maintenance commands for IPSG

Execute display commands in any view and reset commands in user view.

 

Task	Command
Display IPv4SG bindings.	display ip source binding [ static | [ vpn-instance vpn-instance-name ] [ dhcp-relay | dhcp-server ] ] [ ip-address ip-address ] [ mac-address mac-address ] [ vlan vlan-id ] [ interface interface-type interface-number ] [ slot slot-number ]
Display IPv6SG bindings.	display ipv6 source binding [ static | [ vpn-instance vpn-instance-name ] [ dhcpv6-relay ] ] [ ip-address ipv6-address ] [ mac-address mac-address ] [ vlan vlan-id ] [ interface interface-type interface-number ] [ slot slot-number ]

 

IPSG configuration examples

Example: Configuring static IPv4SG

Network configuration

As shown in Figure 2, all hosts use static IP addresses.

Configure static IPv4SG bindings on Device A to meet the following requirements:

·     All interfaces of Device A allow IP packets from Host A to pass.

·     Ten-GigabitEthernet 3/0/1 of Device A allows IP packets from Host B to pass.

Figure 2 Network diagram

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Procedure

# Configure an IP address for each interface. (Details not shown.)

# Enable IPv4SG on Ten-GigabitEthernet 3/0/2.

<DeviceA> system-view

[DeviceA] interface ten-gigabitethernet 3/0/2

[DeviceA-Ten-GigabitEthernet3/0/2] ip verify source ip-address mac-address

[DeviceA-Ten-GigabitEthernet3/0/2] quit

# Configure a static IPv4SG binding for Host A.

[DeviceA] ip source binding ip-address 192.168.0.1 mac-address 0001-0203-0406

# Enable IPv4SG on Ten-GigabitEthernet 3/0/1.

[DeviceA] interface ten-gigabitethernet 3/0/1

[DeviceA-Ten-GigabitEthernet3/0/1] ip verify source ip-address mac-address

# On Ten-GigabitEthernet 3/0/1, configure a static IPv4SG binding for Host B.

[DeviceA] interface ten-gigabitethernet 3/0/1

[DeviceA-Ten-GigabitEthernet3/0/1] ip source binding mac-address 0001-0203-0407

[DeviceA-Ten-GigabitEthernet3/0/1] quit

Verifying the configuration

# Verify that the static IPv4SG bindings are configured successfully on Device A.

<DeviceA> display ip source binding static

Total entries found: 2

IP Address      MAC Address    Interface                VLAN Type

192.168.0.1     0001-0203-0406 N/A                      N/A  Static

N/A             0001-0203-0407 XGE3/0/1                 N/A  Static

Example: Configuring dynamic IPv4SG using DHCP relay agent

Network configuration

As shown in Figure 3, DHCP relay agent is enabled on the router. The host obtains an IP address from the DHCP server through the DHCP relay agent.

Enable dynamic IPv4SG on Ten-GigabitEthernet 3/0/1 to filter incoming packets by using the IPv4SG bindings generated based on DHCP relay entries.

Figure 3 Network diagram

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Procedure

1.     Configure the DHCP relay agent:

# Configure IP addresses for the interfaces. (Details not shown.)

# Enable the DHCP service.

<Router> system-view

[Router] dhcp enable

# Enable recording DHCP relay client entries.

[Router] dhcp relay client-information record

# Configure interface Ten-GigabitEthernet 3/0/1 to operate in DHCP relay mode.

[Router] interface ten-gigabitethernet 3/0/1

[Router-Ten-GigabitEthernet3/0/1] dhcp select relay

# Specify the IP address of the DHCP server.

[Router-Ten-GigabitEthernet3/0/1] dhcp relay server-address 10.1.1.1

[Router-Ten-GigabitEthernet3/0/1] quit

2.     Enable IPv4SG on Ten-GigabitEthernet 3/0/1 and verify the source IP address and MAC address for dynamic IPSG.

[Router] interface ten-gigabitethernet 3/0/1

[Router-Ten-GigabitEthernet3/0/1] ip verify source ip-address mac-address

[Router-Ten-GigabitEthernet3/0/1] quit

Verifying the configuration

# Display dynamic IPv4SG bindings generated based on DHCP relay entries.

[Router] display ip source binding dhcp-relay

Total entries found: 1

IP Address      MAC Address    Interface                VLAN Type

192.168.0.1     0001-0203-0406 XGE3/0/1                 N/A  DHCP relay

The output shows that Ten-GigabitEthernet 3/0/1 will filter packets based on the IPv4SG binding.

Example: Configuring static IPv6SG

Network configuration

As shown in Figure 4, configure a static IPv6SG binding on Ten-GigabitEthernet 3/0/1 of the device to allow only IPv6 packets from the host to pass.

Figure 4 Network diagram

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Procedure

# Enable IPv6SG on Ten-GigabitEthernet 3/0/1.

<Device> system-view

[Device] interface ten-gigabitethernet 3/0/1

[Device-Ten-GigabitEthernet3/0/1] ipv6 verify source ip-address mac-address

# On Ten-GigabitEthernet 3/0/1, configure a static IPv6SG binding for the host.

[Device-Ten-GigabitEthernet3/0/1] ipv6 source binding ip-address 2001::1 mac-address 0001-0202-0202

[Device-Ten-GigabitEthernet3/0/1] quit

Verifying the configuration

# Verify that the static IPv6SG binding is configured successfully on the device.

[Device] display ipv6 source binding static

Total entries found: 1

IPv6 Address         MAC Address    Interface               VLAN Type

2001::1              0001-0202-0202 XGE3/0/1                N/A  Static

Example: Configuring dynamic IPv6SG using DHCPv6 relay agent

Network configuration

As shown in Figure 5, DHCPv6 relay agent is enabled on the router. The clients obtain IPv6 addresses from the DHCPv6 server through the DHCPv6 relay agent.

Enable dynamic IPv6SG on Ten-GigabitEthernet 3/0/1 to filter incoming packets by using the IPv6SG bindings generated based on DHCPv6 relay entries.

Figure 5 Network diagram

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Procedure

1.     Configure the DHCPv6 relay agent:

# Specify IP addresses for the interfaces. (Details not shown.)

# Enable the DHCPv6 relay agent on Ten-GigabitEthernet 3/0/1.

[Router] interface ten-gigabitethernet 3/0/1

[Router-Ten-GigabitEthernet3/0/1] ipv6 dhcp select relay

# Enable recording of DHCPv6 relay entries on the interface.

[Router-Ten-GigabitEthernet3/0/1] ipv6 dhcp relay client-information record

# Specify the DHCPv6 server address 2::2 on the relay agent.

[Router-Ten-GigabitEthernet3/0/1] ipv6 dhcp relay server-address 2::2

[Router-Ten-GigabitEthernet3/0/1] quit

2.     Enable IPv6SG on Ten-GigabitEthernet 3/0/1 and verify the source IP address and MAC address for dynamic IPv6SG.

[Router] interface ten-gigabitethernet 3/0/1

[Router-Ten-GigabitEthernet3/0/1] ipv6 verify source ip-address mac-address

[Router-Ten-GigabitEthernet3/0/1] quit

Verifying the configuration

# Display dynamic IPv6SG bindings generated based on DHCPv6 relay entries.

[Router] display ipv6 source binding dhcpv6-relay

Total entries found: 1

IP Address      MAC Address    Interface                VLAN Type

1::2            0001-0203-0406 XGE3/0/1                 N/A  DHCPv6 relay

The output shows that Ten-GigabitEthernet 3/0/1 will filter packets based on the IPv6SG binding.