I am not very familiar with BGP filters and would like to understand if this type of implementation is possible.
Then if there is some competent person who gives me some advice, all the better.
I have a public AS with a /24 to announce, and I want to make two peers towards the same AS that constitutes my provider, this to have complete redundancy of my border routers.
I am not looking for any balancing but simply a failover in case of failure of one of the two routers.
On the LAN side I chose a VRRP as I cannot do otherwise.
From what I understood, the things to configure for each router are these:
Announce only the /24 towards the outside
Accept only the default route 0.0.0.0/0 to not take charge of the FULL
However, I am missing something because it cannot work like this
Thank you for your reply, since these are agreements already made on the provider side I would like to avoid asking for configuration changes however I read that with a filter of this type it could work “if (dst in 0.0.0.0/0) { accept } else { reject }”
But what do I have to set so that in the event of a failure of one of the two eBGP links the traffic rotates through the iBGP link?
Other manufacturers like Cisco give examples with this type of configuration for Mikrotik I have not found much that does a similar situation
That rule is wrong if you want only default route. That rule will accept all ipv4 routes.
Correct rule would be “if (dst == 0.0.0.0/0) { accept } else { reject }”
But keep in mind that it will still install routes in the routing table as filtered, to save resources it is better to use
input.accept-nlri option in bgp configuration, to accept only NLRI of default route.
