Hi all
I’m back with another question that is probably embarrassingly simple. I’ve got my BGP tables turned up and advertising to our upstream providers, but the router has one RFC1918 subnet logically behind it that I I don’t want included in the BGP advertisements.
I played briefly with filters but that seems like much more than I need. I just need to exclude one internal static route.
It’s a pretty simple layout in that there’s only one routing table (main) and I have 2 BGP peers configured, one on each ISP link.
Thoughts? And, as always, thanks!
I think your only option is to create a filter. There is a remove-private-as option but nothing I’m aware of for filtering prefixes automatically.
Generally it’s considered good practice to always have inbound and outbound routing policy for BGP even if the logic is straightforward for your network. There may be additional safety these days in ROS 7 with RFC 9234 roles, but if you are announcing everything you have without a route policy you run the risk of accidentally becoming a transit AS.
Probably better to specify explicitly the prefixes you originate and only announce them (and you can exclude your private nets that way).