Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements
Webcast-Catalyst9k
New Member

passive-interface with ospf

hello experts

when we issue the command (passive-interface) in ospf configuration on a specific interface, will this command prevent sending and receiving the update packet or prevent sending only and allow for receiving like rip and igrp, thankyou for your response

Labib

2 ACCEPTED SOLUTIONS

Accepted Solutions
Hall of Fame Super Blue

Re: passive-interface with ospf

labibmakar wrote:

hello experts

when we issue the command (passive-interface) in ospf configuration on a specific interface, will this command prevent sending and receiving the update packet or prevent sending only and allow for receiving like rip and igrp, thankyou for your response

Labib

Labib

Passive interface on an OSPF interface will stop it forming any adjacencies/neighborships with other routers on that subnet so it never gets to the stage of sending or receiving routes.

Jon

Hall of Fame Super Silver

Re: passive-interface with ospf

Hello Labib,

OSPF, IS-IS and EIGRP have the neighbor state machine concept: they don't accept routes from a device that doesn't qualify as a neighbor so the passive-interface doesn't allow to have a device listening on the link, as it happens with older and simpler routing protocols like RIP and IGRP.

the passive-interface combined with other commands (protocol dependent) allows to advertise the IP subnet of the involved interface(s).

Hope to help

Giuseppe

5 REPLIES
Hall of Fame Super Blue

Re: passive-interface with ospf

labibmakar wrote:

hello experts

when we issue the command (passive-interface) in ospf configuration on a specific interface, will this command prevent sending and receiving the update packet or prevent sending only and allow for receiving like rip and igrp, thankyou for your response

Labib

Labib

Passive interface on an OSPF interface will stop it forming any adjacencies/neighborships with other routers on that subnet so it never gets to the stage of sending or receiving routes.

Jon

VIP Super Bronze

Re: passive-interface with ospf

Hello Labib,

If you disable the sending of routing updates on an interface, the particular subnet will continue to be advertised to other interfaces, and updates from other routers on that interface continue to be received and processed.

HTH

Reza

Hall of Fame Super Blue

Re: passive-interface with ospf

sharifimr wrote:

Hello Labib,

If you disable the sending of routing updates on an interface, the particular subnet will continue to be advertised to other interfaces, and updates from other routers on that interface continue to be received and processed.

HTH

Reza

Reza

I agree that the subnet will be advertised to other neighbors but no updates on the passive-interface will be received and processed because no adjacency/neighborships can be formed therefore there will be no updates.

Or have i misunderstood what you wrote ?

Jon

VIP Super Bronze

Re: passive-interface with ospf

Jon,

You are right.  It would be on the particular interface only and since there is no adjacency so there will be no other updates.

Thanks for the correction

Reza

Hall of Fame Super Silver

Re: passive-interface with ospf

Hello Labib,

OSPF, IS-IS and EIGRP have the neighbor state machine concept: they don't accept routes from a device that doesn't qualify as a neighbor so the passive-interface doesn't allow to have a device listening on the link, as it happens with older and simpler routing protocols like RIP and IGRP.

the passive-interface combined with other commands (protocol dependent) allows to advertise the IP subnet of the involved interface(s).

Hope to help

Giuseppe

2914
Views
0
Helpful
5
Replies
CreatePlease to create content