ip urpf

Use ip urpf to enable uRPF.

Use undo ip urpf to disable uRPF.

Syntax

ip urpf { loose | strict }

undo ip urpf

Default

uRPF is disabled.

Views

System view

Interface view

Predefined user roles

network-admin

mdc-admin

Parameters

loose: Enables loose uRPF check. To pass loose uRPF check, the source address of a packet must match the destination address of a FIB entry.

strict: Enables strict uRPF check. To pass strict uRPF check, the source address and receiving interface of a packet must match the destination address and output interface of a FIB entry. You can enable strict uRPF check only in VLAN interface view.

Usage guidelines

uRPF can be deployed on a PE connected to a CE or an ISP, or on a CE.

Configure strict uRPF check for traffic that uses symmetric path and configure loose uRPF check for traffic that uses asymmetric path. A symmetric path exists for a session if the PE uses the same interface to receive upstream traffic and send downstream traffic. The path is asymmetric if the PE uses different interfaces to receive upstream traffic and send downstream traffic.

• Typically, symmetric path applies to traffic that goes through an ISP's PE interface connected to the CE. You can configure strict uRPF check on the PE interface.

• Asymmetric path might exist for traffic that goes through a PE interface connected to another ISP. In this case, configure loose uRPF check on the PE interface.

Examples

# Enable strict uRPF check globally.

<Sysname> system-view
[Sysname] ip urpf strict

# Configure loose uRPF check on VLAN-interface 10.

<Sysname> system-view
[Sysname] interface vlan-interface 10
[Sysname-Vlan-interface10] ip urpf loose

Related commands

display ip urpf