Error log:

%BGP-3-NOTIFICATION:received from neighbor 2/2 (peer in wrong as) 2 bytes 0064


The Obvious is true, a wrong ASN is configured, but there is more detail here. “2 bytes 0064” : the 0064 is the received ASN in HEX, ie 0x0064 in HEX = 100 decimal.

The local router is expecting Neighbor to come from a specific ASN, not ASN 100. Have a look at the “neighbor {IP} remote-as” command to confirm it is set correctly. If confederations are used, make sure your confederation-id is correct between the two EBGP peers.