OSPF Basics - passive interface

Using the passive interface or passive enable command in OSPF stops an adjacency forming over a specific router interface. An interface that has been set to passive still has its IP address injected into the OSPF domain and is seen as a STUB network.

This allows interface addresses to be advertised into the OSPF domain but also stops LSA generation / flooding from occurring for interfaces where an adjacency is not expected to be formed.

Differences between IOS XE and IOS XR configuration commands:


router ospf 23
    passive interface default       # enable globally
    passive interface g1            # enable for specific interface
    no passive interface g1         # disable for specific interface


router ospf 23
    passive enable                  # enable globally (all areas / interfaces
    area 11
        passive enable              # enable at area level (interfaces within the area)
        interface <int-id>
            passive enable          # enable for specific interface
            passive disable         # disable for specific interface