PIM Passive

PIM Passive is used to reduce and minimize unnecessary PIM Hello and other PIM control messages.

PIM Passive allows you to specify that the interface is "passive" in regards to PIM. No PIM control packets are sent or processed (if received), but hosts can still send and receive multicast traffic and IGMP control traffic on the interface. Also, PIM Passive prevents any malicious router from taking over as the designated router (DR), which can prevent all hosts on the LAN from joining multicast traffic outside the LAN.

The following guidelines apply to PIM Passive:

  • PIM Passive is a Layer 3 interface [Ethernet/VE] level feature.
  • Because the loopback interfaces are never used to form PIM neighbors, PIM Passive is not supported on loopback interfaces.
  • Both PIM SM and PIM DM modes support PIM Passive.
  • Applying PIM Passive on an interface requires PIM to be enabled on the interface.
  • The sent and received statistics of a PIM Hello message are not changed for an interface while it is configured as PIM passive.
To enable PIM Passive on an interface, enter the following commands:

device# configure terminal
device(config)# router pim
device(config-pim-router)# exit
device(config)# interface ethernet 2
device(config-if-e1000-2)# ip pim
device(config-if-e1000-2)# ip pim passive
device(config-if-e1000-2)# exit
device(config)# interface ve 2
device(config-vif-2)# ip pim-sparse
device(config-vif-2)# ip pim passive
device(config-vif-2)# exit