Not sure if anyone has found a way to find out if the Maximum Prefix Limit has been tripped by a eBGP peer?
We have spoken to MikroTik regarding the Maximum Prefix Limit and they have said the following:-
This implies that they are thinking of removing the Maximum Prefix Limit from RouterOS completely as they think it would be better to filter the prefixes received from external peers.In current version we will not change behavior.. maybe in new routing if there will be max-prefix option at all.
According to RFC when max prefix limit is reached, connection should be closed, which is what RouterOS is doing. In log messages you will see message that max prefix limit is reached and connection closed.
I don't think this will help and I feel that the Maximum Prefix Limit is a VERY important part of any router.
Even if we filtered incoming prefixes it would help, but some peers who we connect with announce 8000+ prefixes to us which would mean a lot of filtering.
If someone has some examples of how they filter incoming routes from external eBGP peers on Public Internet Exchanges (like LINX or DE-CIX) could they share there filters so others can benefit from this.
We are keen to learn more about the filtering capabilities in RouterOS and how to apply the best filters to prefixes received from eBGP peers.
Filters would be great if you only received a few routes from external peers, but some of our peers announce their routes and their customers routes which can add up to a lo of prefixes received.
We don't want to miss any prefixes, but we want to make sure we (and other MikroTik users) don't suffer from a route leak being received from our eBGP peers.
I hope someone will be able to help and shed some light on this.