# Enabling and Disabling RPF Checks

By default, the router accepts multicast packets for each (S,G) pair on an incoming interface (IIF), which satisfies the RPF check (RPF-IIF). When the router performs RPF checks, only the interface that first accepts traffic for an (S,G) pair accepts subsequent traffic for that pair. If traffic stops coming on that interface and starts arriving on another interface, the router does not accept or forward the traffic.

Some network configurations require the router to accept traffic on any interface. To do so, you can disable the RPF check on a specified set of (S,G) pairs by issuing the ipv6 multicast-routing disable-rpf-check command.

When you disable RPF checks, the router accepts multicast packets for (S,G) pairs on any incoming interface. When the router has added the new route to its multicast routing table, it accepts multicast packets for these pairs on any interface in the virtual router and forwards them accordingly. Multicast routes established before you issue this command are not affected.

ipv6 multicast-routing disable-rpf-check

- Use to disable RPF checks for specified (S,G) pairs.
- Specify a standard IPv6 access list that defines the (S,G) pairs.
- Example
  host1(config)#ipv6 multicast-routing disable-rpf-check denver-list
- Use the no version to restore the default situation, in which the router performs RPF checks for all (S,G) pairs.
- See ipv6 multicast-routing disable-rpf-check.