Unicast RPF Loose Mode

Unicast RPF loose mode is similar to unicast RPF strict mode and has the same configuration restrictions. The only check in loose mode is whether the packet has a source address with a corresponding prefix in the routing table; loose mode does not check whether the interface expects to receive a packet with a specific source address prefix. If a corresponding prefix is not found, unicast RPF loose mode does not accept the packet. As in strict mode, loose mode counts the failed packet and optionally forwards it to a fail filter, which either accepts, rejects, logs, samples, or polices the packet.

To configure unicast RPF loose mode, include the mode statement at the [edit interfaces interface-name unit logical-unit-number family (inet | inet6) rpf-check] hierarchy level:

[edit interfaces interface-name unit logical-unit-number family (inet | inet6)]

rpf-check <fail-filter filter-name> {

    mode loose;

}

If you do not include the mode statement in the configuration, unicast RPF uses strict mode by default.