[j-nsp] Weird routing issue on my MX80

[Matthew Crocker]

Hello,

 I have a weird routing issue where my MX80 is not doing what it is supposed to do.   I have a customer configured with BGP announcing two subnets to me.  The subnets end up in the routing table.  One subnet works fine, the other routes to the wrong machine in my network.   Everything looks correct when I 'show route a.b.c.d' but traceroute goes to the wrong machine creating a routing loop.

Is it possible for the FIB to contain different information than what's in 'show route'?
How do I look at whats in the FIB?
How do I reset the FIB and resync it with the actual routes? 

show route A.B.C.0 detail     

inet.0: 439841 destinations, 876907 routes (439825 active, 0 holddown, 32 hidden)
Restart Complete
A.B.C.0/24 (1 entry, 1 announced)
        *BGP    Preference: 170/-101
                Next hop type: Indirect
                Address: 0xdeadbeef
                Next-hop reference count: 6
                Source: X.Y.Z.11
                Next hop type: Router, Next hop index: 1048574
                Next hop: Q.W.E.195 via ge-1/1/1.0
                Next hop: X.Y.Z.11 via ge-1/1/2.0, selected
                Protocol next hop: T.U.V.122
                Indirect next hop: 160865a0 1048575
                State: <Active Int Ext>
                Local AS:  1111 Peer AS:  1111
                Age: 13:39 	Metric: 0 	Metric2: 20 
                Task: BGP_1111.X.Y.Z.11+12834
                Announcement bits (3): 0-KRT 4-BGP RT Background 5-Resolve tree 1 
                AS path: 22222 I
                Accepted
                Localpref: 100
                Router ID: M.N.O.169

The routing table clearly shows two paths X.Y.Z.11 & Q.W.E.195

trace route shows the packets going to X.Y.Z.13 which sends it back to the MX80 and we get a happy routing loop.

The other subnet from the customer looks the same in the show route detail but it gets routed correctly to X.Y.Z.11 and everything is working.

--
Matthew S. Crocker
President
Crocker Communications, Inc.
PO BOX 710
Greenfield, MA 01302-0710

E: matthew at crocker.com
P: (413) 746-2760
F: (413) 746-3704
W: http://www.crocker.com