OSPF

[ITA Terms]

• Description:
• Complete Definition:
• Other routing protocols:

Description:

Open Shortest Path First (OSPF)

Complete Definition:

See also IGP, IS-IS, and RIP.

Other routing protocols:

• EIGRP
• IS-IS
• RIP
• IGRP
• IGP
• BGP

[dahernan]

I want to know why when I configured OSPF process, I usually configure a "default passive" statement. I also configure a "no passive interface" statement on interface which I want OSPF to participate in.  However, in order for OSPF to work in the below configuration, I had to remove the default and the no passive statements.

router ospf 300
 router-id 10.19.xxx.xxx
 auto-cost reference-bandwidth 10000
 area ### stub no-summary
 timers throttle spf 10 100 5000
 timers lsa arrival 80
 network 10.19.xxx.0 0.0.127.255 area ###

I usually configure it as below

 router ospf 300
 router-id 10.19.xxx.xx
 auto-cost reference-bandwidth 10000
 area ### stub no-summary
 timers throttle spf 10 100 5000
 timers lsa arrival 80

 passive-interface default

 no passive-interface TenGigabitEthernet1/1/1
 no passive-interface TenGigabitEthernet1/1/2 
 network 10.19.xxx.0 0.0.127.255 area ###

I tried it the above way and OSPF adjacencies would not form. ???  This is a cisco C9300-24U switch.

[Inderdeep Singh]

Hello, Dahernan

If you want to make router adjacency then no used "no passive-interface" command on that interface in which both routers are connected to each other to make adjacency. By default passive-interface is on in every interface in routers.  

you would remove the "no passive-interface" command on those interface in which you want to create neighbor-ship between routers. After that neighbor-ship will up.

Different between passive and no-passive command are:

1) no passive-interface command on interfaces where adjacency are desired.

2) passive-interface default command to make all interfaces passive by default.

I thing i will be help you. 

[dahernan]

Thanks.