Solved: Turns out I'm an idiot, and

biampcisco · ‎12-28-2015

Setting up a new MPLS circuit. Vendor configures BGP, I configure BGP, we connect, all is well, except I'm not getting all the routes he's advertising to me.

My router: 172.16.55.1 ASN 100
Vendor router: 172.16.55.2 ASN 65333

What I'm receiving and putting into the routing table:

code:

us-2911-1#sh ip bgp neighbors 172.16.55.2 received-routes
BGP table version is 42, local router ID is 68.137.185.66
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *   10.22.55.0/30    172.16.55.2                            0 65333 7385 7385 i
 *   67.136.70.0/29   172.16.55.2                            0 65333 7385 ?
 *   70.98.151.176/29 172.16.55.2              0             0 65333 ?
 *   172.16.55.0/30   172.16.55.2              0             0 65333 ?

Total number of prefixes 4

us-2911-1#sh ip bgp neighbors 172.16.55.2 routes
BGP table version is 42, local router ID is 68.137.185.66
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 *>  10.22.55.0/30    172.16.55.2                          100 65333 7385 7385 i
 *>  67.136.70.0/29   172.16.55.2                          100 65333 7385 ?
 *>  70.98.151.176/29 172.16.55.2              0           100 65333 ?
 *   172.16.55.0/30   172.16.55.2              0           100 65333 ?

Total number of prefixes 4

However, this is what his router is advertising:

code:

145550#show ip bgp neighbors 172.16.55.1 advertised-routes
BGP table version is 93, local router ID is 70.98.151.179
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, x best-external, f RT-Filter
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 10.21.8.0/24     172.16.55.1                            0 100 65000 65000 ?
*> 10.21.12.0/24    172.16.55.1                            0 100 65000 65000 ?
*> 10.21.14.0/24    172.16.55.1                            0 100 65000 65000 ?
*> 10.21.15.0/24    172.16.55.1                            0 100 65000 65000 ?
*> 10.22.0.0/24     172.16.55.1                            0 100 393887 ?
*> 10.22.2.0/24     70.98.151.177                          0 7385 7385 100 ?
*> 10.22.4.0/24     70.98.151.177                          0 7385 7385 100 ?
*> 10.22.55.0/30    70.98.151.178                          0 7385 7385 i
*> 10.30.0.0/16     172.16.55.1                            0 100 65000 65000 ?
*> 10.212.134.0/24  172.16.55.1                            0 100 393887 ?
*> 67.136.70.0/29   70.98.151.177                          0 7385 ?
*> 68.137.185.64/30 172.16.55.1              0             0 100 ?
*> 68.139.88.176/30 172.16.55.1                            0 100 65000 i
*> 70.98.151.176/29 0.0.0.0                  0         32768 ?
*> 100.65.0.4/30    172.16.55.1                            0 100 65001 3549 i
*> 110.143.8.170/32 172.16.55.1                            0 100 65000 65000 ?
*> 124.148.21.4/30  172.16.55.1                            0 100 65000 65000 ?
*> 150.101.32.92/32 172.16.55.1                            0 100 65000 65000 ?
*> 152.161.10.4/30  172.16.55.1                            0 100 65000 ?
*> 172.16.0.0/24    172.16.55.1              0             0 100 ?
*> 172.16.0.0       172.16.55.1              0             0 100 ?
*> 172.16.15.0/24   172.16.55.1              0             0 100 ?
*> 172.16.55.0/30   0.0.0.0                  0         32768 ?
*> 172.18.80.0/24   172.16.55.1              0             0 100 ?
*> 202.45.105.224/32
                    172.16.55.1                            0 100 65000 65000 ?
*> 203.45.253.1/32  172.16.55.1                            0 100 65000 65000 ?

Total number of prefixes 26

Some of those routes are my routes being advertised back to me, no problem, that's normal for BGP, but the routes for 10.22.0.0/24 10.22.2.0/24 and 10.22.4.0/24 are being advertised according to his router, but I'm not seeing them on mine.

So I decide to do a wireshark capture and the first message from him is a BGP update:

code:

Border Gateway Protocol - UPDATE Message
    Marker: ffffffffffffffffffffffffffffffff
    Length: 67
    Type: UPDATE Message (2)
    Withdrawn Routes Length: 0
    Total Path Attribute Length: 32
    Path attributes
        Path Attribute - ORIGIN: INCOMPLETE
            Flags: 0x40, Transitive: Well-known, Transitive, Complete
                0... .... = Optional: Well-known
                .1.. .... = Transitive: Transitive
                ..0. .... = Partial: Complete
                ...0 .... = Length: Regular length
            Type Code: ORIGIN (1)
            Length: 1
            Origin: INCOMPLETE (2)
        Path Attribute - AS_PATH: 65333 7385 7385 100 
            Flags: 0x40, Transitive: Well-known, Transitive, Complete
                0... .... = Optional: Well-known
                .1.. .... = Transitive: Transitive
                ..0. .... = Partial: Complete
                ...0 .... = Length: Regular length
            Type Code: AS_PATH (2)
            Length: 18
            AS Path segment: 65333 7385 7385 100
                Segment type: AS_SEQUENCE (2)
                Segment length (number of ASN): 4
                AS4: 65333
                AS4: 7385
                AS4: 7385
                AS4: 100
        Path Attribute - NEXT_HOP: 172.16.55.2 
            Flags: 0x40, Transitive: Well-known, Transitive, Complete
                0... .... = Optional: Well-known
                .1.. .... = Transitive: Transitive
                ..0. .... = Partial: Complete
                ...0 .... = Length: Regular length
            Type Code: NEXT_HOP (3)
            Length: 4
            Next hop: 172.16.55.2
    Network Layer Reachability Information (NLRI)
        10.22.2.0/24
            NLRI prefix length: 24
            NLRI prefix: 10.22.2.0
        10.22.4.0/24
            NLRI prefix length: 24
            NLRI prefix: 10.22.4.0
        10.22.0.0/24
            NLRI prefix length: 24
            NLRI prefix: 10.22.0.0

So... wtf?

Jon Marshall · ‎12-28-2015

The only routes your router is accepting are those without AS 100 in the path.

An EBGP router will not by default accept routes with it's own AS in the path.

You can change this behaviour but can you clarify that you are the customer connecting to an SP's MPLS network and that you have other sites using the same AS number ?

Jon

View solution in original post

Jon Marshall · ‎12-28-2015

The only routes your router is accepting are those without AS 100 in the path.

An EBGP router will not by default accept routes with it's own AS in the path.

You can change this behaviour but can you clarify that you are the customer connecting to an SP's MPLS network and that you have other sites using the same AS number ?

Jon

biampcisco · ‎12-28-2015

You're correct Jon, I forgot to enable remote-as in for both end points. I honestly thought I had and decided to go over everything again in a lab setup and realized the mistake.

biampcisco · ‎12-28-2015

Turns out I'm an idiot, and forgot to turn on remoteas-in

whoops.

New BGP Peer, not receiving all advertised-routes from neighbor. Help!

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