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New Member

loopback interface need a route?

Dear All,

When I config OSPF, I need to use loopback interface to form the neighbor. But whether I need to confirm that there is a route that can reach the ip of the loopback address? I had find many books but they have no this route. But if the route is not needed. how can the router know the way to the ip address of the loopback interface?

Thank you very much!

Best Regards

Teru Lei

2 ACCEPTED SOLUTIONS

Accepted Solutions

Re: loopback interface need a route?

Generally you configure iBGP neighbors with loopbacks as they are S/W interfaces that never (theoritically) go down.

The loopbacks are then generally learnt via the IGP to obtain a mesh and not advertised via BGP.

It is important to note that you do not have to use loopback interfaces to form relationships it is just a common practice and easier to manage as you know where the route was advertised from.

Re: loopback interface need a route?

When you use BGP, with loopbacks as ip address in remote peer statements, you do need to have a route (atleast a static or learned via IGP). BGP cannot run on its own.

3 REPLIES
New Member

Re: loopback interface need a route?

Sorry for mis type that I am configing BGP, not ospf.

Thank you

Re: loopback interface need a route?

Generally you configure iBGP neighbors with loopbacks as they are S/W interfaces that never (theoritically) go down.

The loopbacks are then generally learnt via the IGP to obtain a mesh and not advertised via BGP.

It is important to note that you do not have to use loopback interfaces to form relationships it is just a common practice and easier to manage as you know where the route was advertised from.

Re: loopback interface need a route?

When you use BGP, with loopbacks as ip address in remote peer statements, you do need to have a route (atleast a static or learned via IGP). BGP cannot run on its own.

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