[j-nsp] Weird routing issue on my MX80

[OBrien, Will]

You should also check for more specific routes inside that block. 
Using a filter that specifies x.x.x.x/24 exact to prevent smaller announcements.

I 

Will O'Brien

On Mar 29, 2013, at 8:16 AM, "Matthew Crocker" <matthew at corp.crocker.com> wrote:

> 
> 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
> 
> 
> 
> 
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