Re: OT - BGP command output interpretation

That is what I needed to hear. So the commands make sense. I am filtering
it (by now allowing it specifically) in a prefix list I have applied
inbound to my BGP. I have found the problem.

THANKS MARKO!

Charles Henson

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  |Marko Milivojevic <markom_at_ipexpert.com> |
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  |Charles.Henson_at_regions.com |
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  |ccielab_at_groupstudy.com |
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| Date: |
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  |03/15/2010 03:12 PM |
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  |Re: OT - BGP command output interpretation |
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Hi,

The command "sh ip bgp nei x.x.x.x received-routes" will show you
prefixes BEFORE they pass through your inbound filters. Do you see
prefix with "sh ip bgp nei x.x.x.x routes". If not, you need to look
at your inbound filtering.

--
Marko Milivojevic - CCIE #18427
Senior Technical Instructor - IPexpert
Mailto: markom_at_ipexpert.com
Telephone: +1.810.326.1444
Fax: +1.810.454.0130
Web: http://www.ipexpert.com/
On Mon, Mar 15, 2010 at 19:59,  <Charles.Henson_at_regions.com> wrote:
> Well... kinda OT..... So I'm troubleshooting some BGP and putting my
study
> skills to good work and having a bit of an issue.
>
> PROBLEM:
> B  B  B  B Router has no 0/0 route. Router is supposed to get 0/0 from
BGP peer.
> Then OSPF on same router (via default information originate) will feed it
> on to WAN. No "always" applied to OSPF Default information originate
> statement.
>
> x.x.x.y is my upstream provider. z.z.z.z is my IBGP peer for redundancy.
I
> see that it is not feeding me any prefixes. Normally I have 1 prefix (the
> 0/0 route) and that is all I need. So the way I'm reading the below
> statement, it looks to me like I'm not being fed any route(s). So if that
> is the case than the below output looks logical and I need to go yell at
my
> carrier.
>
###############################################################################################
> ROUTER-1#show ip bgp summ
> BGP router identifier x.x.x.x, local AS number 9999
> BGP table version is 38, main routing table version 38
> 5 network entries using 585 bytes of memory
> 9 path entries using 468 bytes of memory
> 6/2 BGP path/bestpath attribute entries using 744 bytes of memory
> 1 BGP AS-PATH entries using 24 bytes of memory
> 0 BGP route-map cache entries using 0 bytes of memory
> 0 BGP filter-list cache entries using 0 bytes of memory
> BGP using 1821 total bytes of memory
> 1 received paths for inbound soft reconfiguration
> BGP activity 9/4 prefixes, 42/33 paths, scan interval 60 secs
>
> Neighbor B  B  B  B V B  B AS MsgRcvd MsgSent B  TblVer B InQ OutQ
Up/Down
> State/PfxRcd
> x.x.x.y B  B 4 B 1234 B 137818 B 137857 B  B  B  38 B  B 0 B  B 0
01:52:26 B  B  B  B 0
> z.z.z.z B  B 4 9999 B 137867 B 137858 B  B  B  38 B  B 0 B  B 0 00:01:14
B  B  B  B 4
>
> ROUTER-1#show ip bgp
> BGP table version is 38, local router ID is x.x.x.x
> Status codes: s suppressed, d damped, h history, * valid, > best, i -
> internal,
> B  B  B  B  B  B  B r RIB-failure, S Stale
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
> [NO 0/0 ROUTE. NOTHING TO SEE HERE. MOVE ALONG]
> B  Network B  B  B  B  B Next Hop B  B  B  B  B  B Metric LocPrf Weight
Path
>
>
>
###############################################################################################
>
> BUT WAIT. WHAT IS THIS?
>
> If I hit up my specific neighbor for received routes then BGP reports
that
> it has a 0/0 route from his peer. It's total prefix count is 1. Met and
> local pref 0. That all looks good. The route is valid. But it is not
> flagged as "best".
>
################################################################################################
> ROUTER-1#show ip bgp neighbors B  x.x.x.y received-routes
> BGP table version is 38, local router ID is x.x.x.x
> Status codes: s suppressed, d damped, h history, * valid, > best, i -
> internal,
> B  B  B  B  B  B  B r RIB-failure, S Stale
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
> B  Network B  B  B  B  B Next Hop B  B  B  B  B  B Metric LocPrf Weight
Path
> * B 0.0.0.0 B  B  B  B  B x.x.x.y B  B  B  B  B  B  0 B  B  B  B  B  B  0
1234 i
>
> Total number of prefixes 1
>
################################################################################################
>
> So my BGP summary commands sho zero prefixes being received by me. But my
> neighbor specific command shows the 0/0 being received and the prefixes
> totalling 1. This is my problem. The 0/0 route appears there but it's not
> getting passed to the RIB. Now I have no other static or dynamic 0/0
routes
> or anything else with a lower AD. I have no RIB failures.
>
> 1. Am I understanding the command output above correctly? I believe that
I
> am based on CCO and checking with my local Cisco guy. He's nosing around
as
> well but feels that something is amiss here.
>
> 2. If I (we) are interpreting the command output above correctly, then
does
> the conflict between the commands make sense? Any thoughts?
>
> I have bounced the router and still have the same issue. To bring things
up
> I have added a static to to see if that would work. It did. So the next
hop
> is valid. Anyone?
>
> [IP addressing and ASNs have been changed to protect the innocent. Yes, I
> am aware that some creative googling will reveal all anyway.]
>
>
> Charles Henson
>
>
> Blogs and organic groups at http://www.ccie.net
>
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