BGP - Advertise a prefix to only one upstream

RouterOS Forwarding Protocols
1

Hello,

I have two upstreams that they provide me a BGP session to advertise my prefixes.

I have multiple prefixes.

I want, advertise some prefixes to one upstream and other prefixes to the other.

How to do?

For example:

Prefix: 1.1.1.0/24 advertise to AS1
Prefix: 2.2.2.0/24 advertise to AS2
Prefix: 3.3.3.0/24 advertise to AS1 and AS2

Currently what I have is:

/routing filter
add action=accept chain=AS1-IN prefix=0.0.0.0/0
add action=accept chain=AS1-OUT prefix=1.1.1.0/24
add action=accept chain=AS1-OUT prefix=3.3.3.0/24
add action=discard chain=AS1-OUT
add action=accept chain=AS2-IN prefix=0.0.0.0/0
add action=accept chain=AS2-OUT prefix=2.2.2.0/24
add action=accept chain=AS2-OUT prefix=3.3.3.0/24
add action=discard chain=AS2-OUT

But I’m doing something wrong… bacause filters don’t take effect.
2.2.2.0/24 is also going on AS1
and 1.1.1.0/24 is also going on AS2

I’ve tried to disable all filters, and don’t take effect… all is running “fine” → All networks work on all upstreams.

Thanks in advance!

2

Your out filters are correct… if the only problem is that you are still advertising all of your prefixes to both providers, then I suggest you bounce one of the BGP sessions to confirm the filters taking affect (this is the brute force way of doing it).

3

Did you apply the filters to your BGP peers as out-filter and reset the BGP sessions ?