BGP policies for routing

Here are some ways to control the way of BGP routing and sending updates to neighbors or controling updates from neighbors.

With „distribute-list“ it’s possbile to controll routes coming in on an interface or routes going out on an interface. You can for example say:

I don’t want to send route „192.168.1.0/24“ to router A an s0/0. So your distribute-list would look like:

(config)# acces-list 10 deny 192.168.1.0 0.0.0.255
(config)# access-list 10 any any
(config)# router bgp 500
(config-router)# distribute-list 10 out s0/0

So A would not receive 192.168.1.0

There are prefix lists are very similiar to acl’s. But they allow for example the use of sequence numbers. So you can a prefix-list inbetween other lists and don’t have to apply them at the end, like with acl’s.

Prefix-lists are more designed to filter route information.

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