Command Reference Guide

3Com Router 5000 Family and Router 6000 Family ip urpf ● 205
Command Reference
ip urpf
Purpose Use the ip urpf command to enable URPF check on the interface.
Use the undo ip urpf command to disable URPF check.
Syntax ip urpf { strict | loose } [ allow-default ] [ acl acl-number ]
undo ip urpf
Parameters strict
Strict check. The packet’s source address must be in
the router’s FIB table. It searches reversely for outgoing
interfaces for the packet. At least one outgoing
address must match the packet’s incoming interface;
otherwise URPF rejects the packet.
loose
Loose check. The only requirement is that the packet’s
source address is in the router’s FIB table; otherwise
URPF rejects the packet.
allow-default
Allows special treatment for the default route. When
the default route and the allow-default parameters are
both configured, the principles of strict check and
loose check change.
acl-number
ACL number. Valid values are 2000 to 3999.
Default By default, URPF is disabled.
Example Enable strict URPF check on Ethernet2/2/0, allow special treatment for the default
route, and set ACL number to 2999.
[3Com-Ethernet2/2/0] ip urpf strict allow-default acl 2999
View This command can be used in the following views:
■ Interface view