Configuring Passive Interface

Configuring Passive Interface suppresses routing updates on all interfaces.

Parent topic: Configuring OSPF

Suppressing Routing Updates on All Interfaces

  1. Execute the following commands to suppress routing updates on all interfaces.

    Type the following:

    • Enter the Global Configuration Mode in ISS1.
    iS5comm# configure terminal
    • Enable OSPF globally in the switch ISS1.
    iS5comm(config)# router ospf
    • Suppress routing updates by executing the following command.
    iS5comm(config-if)# passive-interface default
    Note:

    All OSPF interfaces created after the execution of this command will be passive. This is useful for an Internet service provider (ISP) and large enterprise networks where many of the distribution routers have more than 200 interfaces.

    iS5comm(config-if)# network 10.4.0.1 area 0.0.0.0
    • Exit from the Interface Configuration mode.
    iS5comm(config-if)# end
  2. View the configuration details by executing the following show command.

    Type the following:

    iS5comm# show ip ospf interface vlan 1
    vlan1 is line protocol is up 
    Internet Address 10.4.0.1, Mask 255.255.0.0, Area 0.0.0.0
    AS 1, Router ID ID 10.10.2.1, Network Type BROADCAST, Cost 1
    Transmit Delay is 1 sec, State 2, Priority 1 
    No designated router on this network
    No backup designated router on this network 
    Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 
    No Hellos (Passive interface) 
    Neighbor Count is 0, Adjacent neighbor count is 0
  3. Restore routing updates on all interfaces by executing the following commands.

    Type the following:

    iS5comm(config-if)# no network 10.4.0.1 area 0.0.0.0
    iS5comm(config-if)# no passive-interface default

Suppressing Routing Updates on a Specific Interface

It is also possible to suppress routing updates on a specified interface.

  1. Execute the following commands to suppress routing updates on a Specific Interface.

    Type the following:

    • Enter the Global Configuration Mode in ISS1.
    iS5comm# configure terminal
    • Enable OSPF globally in the switch ISS1.
    iS5comm(config)# router ospf
    • Enter the Interface Configuration Mode for VLAN 1.
    iS5comm(config)# interface vlan 1
    iS5comm(config-if)# network 10.4.0.1 area 0.0.0.0
    • Configure the VLAN 1 interface as passive interface.
    iS5comm(config-if)# passive-interface vlan 1
    • Exit from the Interface Configuration mode.
    iS5comm(config-if)# end
  2. View the configuration details by executing the following show command.

    Type the following:

    iS5comm# show ip ospf interface vlan 1
    vlan1 is line protocol is up 
    Internet Address 10.4.0.1, Mask 255.255.0.0, Area 0.0.0.0
    AS 1, Router ID ID 10.10.2.1, Network Type BROADCAST, Cost 1
    Transmit Delay is 1 sec, State 2, Priority 1 
    No designated router on this network
    No backup designated router on this network 
    Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 
    No Hellos (Passive interface) 
    Neighbor Count is 0, Adjacent neighbor count is 0
  3. Restore routing updates on all interfaces by executing the following commands.

    Type the following:

    iS5comm(config-if)# no passive-interface vlan 1