09-Security Configuration Guide

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10-IP source guard configuration
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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 implement the following functions:

·     Filter incoming IPv4 or IPv6 packets on the interface.

·     Cooperate with ARP attack detection in IPv4 for user validity checking. For information about ARP attack detection, see "Configuring ARP attack protection."

·     Cooperate with ND attack detection in IPv6 for user validity checking. For information about ND attack detection, see "Configuring ND attack defense."

Static IPSG bindings can be global or interface-specific.

·     Global static binding—Binds the IP address and MAC address in system view. The binding takes effect on all interfaces to filter packets for user spoofing attack prevention.

·     Interface-specific static binding—Binds the IP address, MAC address, VLAN, 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 snooping, DHCPv4 relay agent, DHCPv6 snooping, 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, the DHCP snooping device, or the DHCP relay agent. It generates dynamic bindings based on the client bindings on the DHCP server, the DHCP snooping entries, 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:

Interface types

Source modules

Binding usage

Layer 2 Ethernet interface

DHCP snooping

ARP snooping

Packet filtering.

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.

For information about ARP snooping, DHCP snooping, 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:

Interface types

Source modules

Layer 2 Ethernet interface

DHCPv6 snooping

ND snooping

Layer 3 Ethernet interface

VLAN interface

DHCPv6 relay agent

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

Restrictions and guidelines: IPSG configuration

You cannot configure the IPSG feature on a service loopback interface. If IPSG is enabled on an interface, you cannot assign the interface to a service loopback group.

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 ARP snooping, DHCP snooping, 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 2 Ethernet interface.

¡     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 | ip-address mac-address | mac-address }

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

Configuring a static IPv4SG binding

About this task

You can configure global static and interface-specific static IPv4SG bindings. Interface-specific static and dynamic bindings take priority over global static bindings. An interface first uses the static and dynamic bindings on the interface to match packets. If no match is found, the interface uses the global bindings.

Restrictions and guidelines

Global static bindings take effect on all interfaces on the device.

To configure a static IPv4SG binding for the ARP attack detection feature, make sure the following conditions are met:

·     The ip-address ip-address option, the mac-address mac-address option, and the vlan vlan-id option must be specified.

·     ARP attack detection must be enabled for the specified VLAN.

Configuring a global static IPv4SG binding

1.     Enter system view.

system-view

2.     Configure a global static IPv4SG binding.

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

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 2 Ethernet interface.

¡     Layer 3 Ethernet interface.

¡     Layer 3 Ethernet subinterface.

¡     Layer 3 aggregate interface.

¡     Layer 3 aggregate subinterface.

¡     VLAN interface..

3.     Configure a static IPv4SG binding.

ip source binding { ip-address ip-address | ip-address ip-address mac-address mac-address | mac-address mac-address } [ vlan vlan-id ]

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 snooping, DHCPv6 relay agent, or ND snooping 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 2 Ethernet interface.

¡     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 | ip-address mac-address | mac-address }

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

Configuring a static IPv6SG binding

About this task

You can configure global static and interface-specific static IPv6SG bindings. Interface-specific static and dynamic bindings take priority over global static bindings. An interface first uses the static and dynamic bindings on the interface to match packets. If no match is found, the interface uses the global bindings.

Restrictions and guidelines

Global static bindings take effect on all interfaces on the device.

To configure a static IPv6SG binding for the ND attack detection feature, the vlan vlan-id option must be specified, and ND attack detection must be enabled for the specified VLAN.

Configuring a global static IPv6SG binding

1.     Enter system view.

system-view

2.     Configure a global static IPv6SG binding.

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

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 2 Ethernet interface.

¡     Layer 3 Ethernet interface.

¡     Layer 3 Ethernet subinterface.

¡     Layer 3 aggregate interface.

¡     Layer 3 aggregate subinterface.

¡     VLAN interface.

3.     Configure a static IPv6SG binding.

ipv6 source binding { ip-address ipv6-address | ip-address ipv6-address mac-address mac-address | mac-address mac-address } [ vlan vlan-id ]

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 ] [ arp-snooping | dhcp-relay | dhcp-server | dhcp-snooping ] ] [ 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 | dhcpv6-snooping | nd-snooping ] ] [ 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.

·     HundredGigE 1/0/1 of Device A allows IP packets from Host B to pass.

Figure 2 Network diagram

Procedure

IMPORTANT

IMPORTANT:

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

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

# Enable IPv4SG on HundredGigE 1/0/2.

<DeviceA> system-view

[DeviceA] interface hundredgige 1/0/2

[DeviceA-HundredGigE1/0/2] ip verify source ip-address mac-address

[DeviceA-HundredGigE1/0/2] 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 HundredGigE 1/0/1.

[DeviceA] interface hundredgige 1/0/1

[DeviceA-HundredGigE1/0/1] ip verify source ip-address mac-address

# On HundredGigE 1/0/1, configure a static IPv4SG binding for Host B.

[DeviceA] interface hundredgige 1/0/1

[DeviceA-HundredGigE1/0/1] ip source binding mac-address 0001-0203-0407

[DeviceA-HundredGigE1/0/1] 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 HGE1/0/1                 N/A  Static

Example: Configuring dynamic IPv4SG using DHCP snooping

Network configuration

As shown in Figure 3, the host (the DHCP client) obtains an IP address from the DHCP server. Perform the following tasks:

·     Enable DHCP snooping on the device to make sure the DHCP client obtains an IP address from the authorized DHCP server. To generate a DHCP snooping entry for the DHCP client, enable recording of client information in DHCP snooping entries.

·     Enable dynamic IPv4SG on HundredGigE 1/0/1 to filter incoming packets by using the IPv4SG bindings generated based on DHCP snooping entries. Only packets from the DHCP client are allowed to pass.

Figure 3 Network diagram

Procedure

IMPORTANT

IMPORTANT:

·     By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

·     Physical interfaces in this example must operate in Layer 2 mode. By default, physical interfaces on the device operate in Layer 3 mode. To change the operation mode for physical interfaces, you must use the port link-mode command in interface view.

1.     Configure the DHCP server.

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

2.     Configure the device:

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

# Enable DHCP snooping.

<Device> system-view

[Device] dhcp snooping enable

# Configure HundredGigE 1/0/2 as a trusted interface.

[Device] interface hundredgige 1/0/2

[Device-HundredGigE1/0/2] dhcp snooping trust

[Device-HundredGigE1/0/2] quit

# Enable IPv4SG on HundredGigE 1/0/1 and verify the source IP address and MAC address for dynamic IPSG.

[Device] interface hundredgige 1/0/1

[Device-HundredGigE1/0/1] ip verify source ip-address mac-address

# Enable recording of client information in DHCP snooping entries on HundredGigE 1/0/1.

[Device-HundredGigE1/0/1] dhcp snooping binding record

[Device-HundredGigE1/0/1] quit

Verifying the configuration

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

[Device] display ip source binding dhcp-snooping

Total entries found: 1

IP Address      MAC Address    Interface                VLAN Type

192.168.0.1     0001-0203-0406 HGE1/0/1                 1    DHCP snooping

The output shows that HundredGigE 1/0/1 will filter packets based on the IPv4SG binding.

Example: Configuring dynamic IPv4SG using DHCP relay agent

Network configuration

As shown in Figure 4, 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 HundredGigE 1/0/1 to filter incoming packets by using the IPv4SG bindings generated based on DHCP relay entries.

Figure 4 Network diagram

Procedure

IMPORTANT

IMPORTANT:

·     By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

·     Physical interfaces in this example must operate in Layer 2 mode. By default, physical interfaces on the device operate in Layer 3 mode. To change the operation mode for physical interfaces, you must use the port link-mode command in interface view.

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 HundredGigE 1/0/1 to operate in DHCP relay mode.

[Router] interface hundredgige 1/0/1

[Router-HundredGigE1/0/1] dhcp select relay

# Specify the IP address of the DHCP server.

[Router-HundredGigE1/0/1] dhcp relay server-address 10.1.1.1

[Router-HundredGigE1/0/1] quit

2.     Enable IPv4SG on HundredGigE 1/0/1 and verify the source IP address and MAC address for dynamic IPSG.

[Router] interface hundredgige 1/0/1

[Router-HundredGigE1/0/1] ip verify source ip-address mac-address

[Router-HundredGigE1/0/1] 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 HGE1/0/1                 N/A  DHCP relay

The output shows that HundredGigE 1/0/1 will filter packets based on the IPv4SG binding.

Example: Configuring static IPv6SG

Network configuration

As shown in Figure 5, configure a static IPv6SG binding on HundredGigE 1/0/1 of the device to allow only IPv6 packets from the host to pass.

Figure 5 Network diagram

Procedure

IMPORTANT

IMPORTANT:

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

# Enable IPv6SG on HundredGigE 1/0/1.

<Device> system-view

[Device] interface hundredgige 1/0/1

[Device-HundredGigE1/0/1] ipv6 verify source ip-address mac-address

# On HundredGigE 1/0/1, configure a static IPv6SG binding for the host.

[Device-HundredGigE1/0/1] ipv6 source binding ip-address 2001::1 mac-address 0001-0202-0202

[Device-HundredGigE1/0/1] 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 HGE1/0/1                N/A  Static

Example: Configuring dynamic IPv6SG using DHCPv6 snooping

Network configuration

As shown in Figure 6, the host (the DHCPv6 client) obtains an IP address from the DHCPv6 server. Perform the following tasks:

·     Enable DHCPv6 snooping on the device to make sure the DHCPv6 client obtains an IPv6 address from the authorized DHCPv6 server. To generate a DHCPv6 snooping entry for the DHCPv6 client, enable recording of client information in DHCPv6 snooping entries.

·     Enable dynamic IPv6SG on HundredGigE 1/0/1 to filter incoming packets by using the IPv6SG bindings generated based on DHCPv6 snooping entries. Only packets from the DHCPv6 client are allowed to pass.

Figure 6 Network diagram

Procedure

IMPORTANT

IMPORTANT:

·     By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

·     Physical interfaces in this example must operate in Layer 2 mode. By default, physical interfaces on the device operate in Layer 3 mode. To change the operation mode for physical interfaces, you must use the port link-mode command in interface view.

1.     Configure DHCPv6 snooping:

# Enable DHCPv6 snooping globally.

<Device> system-view

[Device] ipv6 dhcp snooping enable

# Configure HundredGigE 1/0/2 as a trusted interface.

[Device] interface hundredgige 1/0/2

[Device-HundredGigE1/0/2] ipv6 dhcp snooping trust

[Device-HundredGigE1/0/2] quit

2.     Enable IPv6SG:

# Enable IPv6SG on HundredGigE 1/0/1 and verify the source IP address and MAC address for dynamic IPv6SG.

[Device] interface hundredgige 1/0/1

[Device-HundredGigE1/0/1] ipv6 verify source ip-address mac-address

# Enable recording of client information in DHCPv6 snooping entries on HundredGigE 1/0/1.

[Device-HundredGigE1/0/1] ipv6 dhcp snooping binding record

[Device-HundredGigE1/0/1] quit

Verifying the configuration

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

[Device] display ipv6 source binding dhcpv6-snooping

Total entries found: 1

IPv6 Address         MAC Address    Interface               VLAN Type

2001::1              040a-0000-0001 HGE1/0/1                1    DHCPv6 snooping

The output shows that HundredGigE 1/0/1 will filter packets based on the IPv6SG binding.

Example: Configuring dynamic IPv6SG using DHCPv6 relay agent

Network configuration

As shown in Figure 7, 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 HundredGigE 1/0/1 to filter incoming packets by using the IPv6SG bindings generated based on DHCPv6 relay entries.

Figure 7 Network diagram

Procedure

IMPORTANT

IMPORTANT:

By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

1.     Configure the DHCPv6 relay agent:

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

# Enable the DHCPv6 relay agent on HundredGigE 1/0/1.

[Router] interface hundredgige 1/0/1

[Router-HundredGigE1/0/1] ipv6 dhcp select relay

# Enable recording of DHCPv6 relay entries on the interface.

[Router-HundredGigE1/0/1] ipv6 dhcp relay client-information record

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

[Router-HundredGigE1/0/1] ipv6 dhcp relay server-address 2::2

[Router-HundredGigE1/0/1] quit

2.     Enable IPv6SG on HundredGigE 1/0/1 and verify the source IP address and MAC address for dynamic IPv6SG.

[Router] interface hundredgige 1/0/1

[Router-HundredGigE1/0/1] ipv6 verify source ip-address mac-address

[Router-HundredGigE1/0/1] 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 HGE1/0/1                 N/A  DHCPv6 relay

The output shows that HundredGigE 1/0/1 will filter packets based on the IPv6SG binding.

 

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