BGP Filtering on google cloud routers

Question

When using a BGP cloud router on GCP, is there a way to filter incoming routes? Otherwise this can cause problems if the other end sends more routes than you expect.

Answer 1

According to the official documentation you can enable dynamic routing when you have created the Cloud Router and the BGP, once the connection is set between the router and the on-premises, Cloud Router learns the on-premises routes through BGP and enables the network infrastructure to select the best route.

If you want to literally filter traffic the only way to do that is at the firewall on-premises or the firewall on the VPC, filtering is not possible at the Cloud Router level because this is just the connection between the two ends.

For something different than this, you should explain a bit more your use case.

Answer 2

At this time there is no way to filter incoming routes learnt via BGP. This sucks, and means if your BGP peer is advertising more than 100 prefixes, you'll learn them seemingly in the order they are sent and any over the first 100 are simply listed with their status of 'dropped' in the dynamic routing screen on the gcp console.