Bad remote-as

RouterOS Forwarding Protocols
1

I’m stumped. Either I’m missing something or the remote peer is configured wrong.

Initially I was getting:

00:05:11 route,bgp,error Received notification 
00:05:11 route,bgp,error     OPEN error: bad remote-as

so after a little playing I intentionally broke the remote as and got:

00:00:21 route,bgp,error Invalid remote AS, expected 29950 
00:00:21 route,bgp,error     RemoteAddress=1.1.1.64 
00:00:21 route,bgp,error     RemoteAs=29951

AS 29951 is indeed that correct AS so I changed the peer config back, but the original error is still present. Here is the full debug, does anyone else see something I’m missing or any suggestions on what I might try?


00:05:10 system,info bgp peer blah changed by admin 
00:05:11 route,bgp,debug Update source 
00:05:11 route,bgp,debug     Address=1.1.1.181 
00:05:11 route,bgp,debug Connecting 
00:05:11 route,bgp,debug     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,state Entering Connect state 
00:05:11 route,bgp,debug,state     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,info TCP connection established 
00:05:11 route,bgp,info     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,state Entering OpenSent state 
00:05:11 route,bgp,debug,state     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet,raw Sent OPEN message 
00:05:11 route,bgp,debug,packet,raw     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet,raw     Length=45 
00:05:11 route,bgp,debug,packet,raw     FF FF FF FF FF FF FF FF FF FF FF FF FF FF 
FF FF 
00:05:11 route,bgp,debug,packet,raw     00 2D 01 04 D7 04 00 B4 43 8A 6F 8C 10 02 
0E 02 
00:05:11 route,bgp,debug,packet,raw     00 41 04 00 00 D7 04 01 04 00 01 00 01 
00:05:11 route,bgp,debug,packet Sent OPEN message 
00:05:11 route,bgp,debug,packet     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet     Length=45 
00:05:11 route,bgp,debug,packet OPEN Message 
00:05:11 route,bgp,debug,packet     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet     MessageLength=45 
00:05:11 route,bgp,debug,packet,raw Received OPEN packet 
00:05:11 route,bgp,debug,packet,raw     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet,raw     Length=45 
00:05:11 route,bgp,debug,packet,raw     FF FF FF FF FF FF FF FF FF FF FF FF FF FF 
FF FF 
00:05:11 route,bgp,debug,packet,raw     00 2D 01 04 74 FF 00 5A 45 1B AD 22 10 02 
0E 01 
00:05:11 route,bgp,debug,packet,raw     04 00 01 00 01 02 00 41 04 00 00 74 FF 
00:05:11 route,bgp,debug,packet OPEN Message capabilities option 
00:05:11 route,bgp,debug,packet     Lenght=14 
00:05:11 route,bgp,debug,packet OPEN Message capability 
00:05:11 route,bgp,debug,packet     Code=multiprotocol capability 
00:05:11 route,bgp,debug,packet     Lenght=4 
00:05:11 route,bgp,debug,packet OPEN Message capability 
00:05:11 route,bgp,debug,packet     Code=route refresh capability 
00:05:11 route,bgp,debug,packet     Lenght=0 
00:05:11 route,bgp,debug,packet OPEN Message capability 
00:05:11 route,bgp,debug,packet     Code=AS 4-octet capability 
00:05:11 route,bgp,debug,packet     Lenght=4 
00:05:11 route,bgp,debug,state Entering OpenConfirm state 
00:05:11 route,bgp,debug,state     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet,raw Sent KEEPALIVE message 
00:05:11 route,bgp,debug,packet,raw     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet,raw     Length=19 
00:05:11 route,bgp,debug,packet,raw     FF FF FF FF FF FF FF FF FF FF FF FF FF FF 
FF FF 
00:05:11 route,bgp,debug,packet,raw     00 13 04 
00:05:11 route,bgp,debug,packet Sent KEEPALIVE message 
00:05:11 route,bgp,debug,packet     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet     Length=19 
00:05:11 route,bgp,debug,packet NOTIFICATION Message 
00:05:11 route,bgp,debug,packet     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet     MessageLength=21 
00:05:11 route,bgp,debug,packet,raw Received NOTIFICATION packet 
00:05:11 route,bgp,debug,packet,raw     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet,raw     Length=21 
00:05:11 route,bgp,debug,packet,raw     FF FF FF FF FF FF FF FF FF FF FF FF FF FF 
FF FF 
00:05:11 route,bgp,debug,packet,raw     00 15 03 02 02 
00:05:11 route,bgp,error Received notification 
00:05:11 route,bgp,error     OPEN error: bad remote-as 
00:05:11 route,bgp,debug,state Entering Idle state 
00:05:11 route,bgp,debug,state     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet,raw Sent NOTIFICATION message 
00:05:11 route,bgp,debug,packet,raw     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet,raw     Length=21 
00:05:11 route,bgp,debug,packet,raw     cease, subcode=0 
00:05:11 route,bgp,debug,packet,raw     FF FF FF FF FF FF FF FF FF FF FF FF FF FF 
FF FF 
00:05:11 route,bgp,debug,packet,raw     00 15 03 06 00 
00:05:11 route,bgp,debug,packet Sent NOTIFICATION message 
00:05:11 route,bgp,debug,packet     RemoteAddress=1.1.1.64 
00:05:11 route,bgp,debug,packet     Length=21
2

You have configured wrong AS numbers

You are trying to connect to 29950 but remote peer has 29951

3

Yes, I intentionally broke it to see if the error changed. When I intentionally misconfigured it for remote as 29950 the error is very clear that 29950 is wrong. But when I change it to the correct ASN (29951) I continue to get a remote ASN error but without anything specific mentioned as the problem.

I’m really leaning toward a provider config issue, but even that isn’t clear from any of the errors.

4

And did you set correct AS number on your router in BGP instance config?

5

Yup. I’m leaning toward the provider doesn’t have the remote ASN set correctly (my correct ASN), would this be your conclusion as well?

 0 *  name="default" as=55044 router-id=1.1.1.181 redistribute-connected=no 
      redistribute-static=no redistribute-rip=no redistribute-ospf=no 
      redistribute-other-bgp=no out-filter="" client-to-client-reflection=yes 
      ignore-as-path-len=no routing-table="" 
[admin@MikroTik] /routing bgp> peer print
Flags: X - disabled, E - established 
 #   INSTANCE         REMOTE-ADDRESS                                  REMOTE-AS  
 0   default          1.1.1.64                                   29951
6

00:05:11 route,bgp,error Received notification
00:05:11 route,bgp,error OPEN error: bad remote-as

It does appear the remote side has misconfigured your AS,
(assuming your AS is 55044)

7

The remote side had configured our peer ASN to be the same as theirs.

Thanks for the help, I thought it was on their side, but I like to have another opinion before confronting a provider.