Dear ALL,

We have two ccr1009(Version 6.37.1) and running iBGP a year normally, but today we found the BGP session is established
, RouterA can receive the prefix from Router B, but Router B can’t receive the prefix from Router A.
Anyone can help to troubleshoot the problem?

TungHo

Do you have any filters applied? If yes, check what is being advertised to router B from A against the filter.

Are the prefixes from router A locally generated or are they learned from some other router? If they are learned from another iBGP router they wont be forwarded unless they are reflected.

There are a number of reasons why prefixes wouldn't be advertised, can you provide any more info?

Has any of your configuration changed?

If not, i'd disable and re-enable the peering and then upgrade to the latest bugfix version of ROuterOS

Has any of your configuration changed?
TungHo: No, haven't change the setting over a year.

If not, i'd disable and re-enable the peering and then upgrade to the latest bugfix version of ROuterOS

tungHo: i have try to disable and re-enable the peer at that moment, but still can't receive the prefix from Router A. I just updated the version to v6.39.2, hope can fix the problem.

TungHo