I have two bgp routers. OSPF as IGP and on Loopback's iBGP. Both routers have different peers, but both receive full routing table.

In google I found on many presantations "bgp best practisec" that they set: distance bgp 200 200 200 As I understand to give priority to IGP in my case OSPF routes, correct? Because in other case can BGP look for my internal routes in through ebgp session? instead to IPs in my prefix to go through ospf it will want to push traffic through egbp because will see my prefixes in another peer? Why it is good practise to set distance bgp 200 200 200 ?

https://nsrc.org/workshops/2017/apricot2017/bgp/bgp/preso/05-BGP-BCP.pdf page 4


The presentation you quote from (I could only find one, not many) is aimed at ISPs. They have different requirements and circumstances than enterprise networks.

In this case, The ISP is using the IGP for its internal routing, and using BGP to carry its customer routes. These routes are kept separate -- internal equipment doesn't need to know about customer routes and vice versa. The reason eBGP has a high AD is to insure that customer routes never interfere with the ISPs internal routing. This makes the ISPs network more stable because customer routes can't accidentally replace internal routes.


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