Ip Verify Unicast Source Reachable-Via - Cisco Catalyst 4500 Series Command Reference Manual

ip verify unicast source reachable-via

ip verify unicast source reachable-via
To enable and configure unicast RPF checks on a IPv4 interface, use the ip verify unicast source
reachable-via command. To disable unicast RPF, use the no form of this command.
Syntax Description
rx
allow-default
Defaults Disabled
Command Modes Interface configuration mode
Command History Release
12.2(40)SG
Usage Guidelines In basic RX mode, unicast RPF ensures a source address must be reachable on the arrived interface. For
example, the source must be reachable without load balancing.
Unicast RPF is an input function and is applied only on the input interface of a router at the upstream
Note
end of a connection.
Do not use unicast RPF on internal network interfaces. Internal interfaces might have routing asymmetry,
which means that there are multiple routes to the source of a packet. Apply unicast RPF only where there
is natural or configured symmetry.
Examples
This example shows how to enable unicast RPF exist-only checking mode:
Switch# configure terminal
Enter configuration commands, one per line.
Switch(config)# interface gigabitethernet1/1
Switch(config-if)# ip verify unicast source reachable-via rx allow-default
Switch(config-if)# end
Switch#
Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.4.0SG and IOS 15.1(2)SG)
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ip verify unicast source reachable-via rx allow-default
no ip verify unicast source reachable-via
Verifies that the source address is reachable on the interface where the packet was
received.
Verifies that the default route matches the source address.
Modification
Support introduced on Catalyst 4900M chassis and a Catalyst 4500 with a
Supervisor Engine 6-E.
Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
End with CNTL/Z.
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