Usage Scenario
To prevent malicious hosts from constructing pseudo PIM Hello messages to attack a router, enable PIM silent using the pim silent command on an interface connected to hosts. After PIM silent is enabled on an interface, all PIM packets will be discard by this interface, and all PIM neighbors and PIM state machines will be deleted for this interface. The interface automatically becomes a static designated router (DR). IGMP functions, however, are not affected on the interface.
Precautions
PIM silent applies only to interfaces directly connected to a host network segment on which only one PIM device is deployed.
- The pim silent command is mutually exclusive with the pim timer dr-switch-delay command.
- The pim silent command is mutually exclusive with the pim dm command.
- The pim silent command is mutually exclusive with the pim bfd enable command.
If PIM silent is enabled on an interface connected to a router, a PIM neighbor relationship cannot be set up on the interface, causing multicast faults.
If a host network segment connects to multiple routers and PIM silent is enabled on interfaces of multiple routers, all these interfaces become static DRs, causing multicast faults.