[c-nsp] bgp config [continue]

Shaun Reitan mailinglists at unix-scripts.com
Thu Aug 4 19:01:20 EDT 2005


I'm setting up bgp between me and a guy I know.  On his end he has a
connection with Cox and then has a DS3 running to me.  The connection with
Cox is his primary connection and only wants to use the ds3 as fail-over.  I
setup bgp and for the most part it looks like it's working but there are a
few problems I'm running into.  First alittle run down, I am only sending a
default 0.0.0.0 route, and he is only receiving a default 0.0.0.0 route from
both me and his other provider.  On my nei he has a route-map called backup
set on out.  The only thing in this route-map is a as-path prepend with his
asn 3 times.  He also has route-map on COX called local-pref set on in.
local-pref only has a set local-preference 200 in it.

The problems i've been having are the following.

When turning bgp up the first problem I see is that customers in my address
space cannot trace to his address space, they can ping.  I think I narrowed
this problem down, I think what is happening is that my route see's his ip
space as bring across the ds3 (a sh ip bgp shows his ip space having a *> to
his side of bgp nei) and sends the packets across the ds3, but then his
router listens to the route-maps and sends back across Cox.  A few reasons
why I think this, 1 being that if I set a static route on his router routing
my ip space back through the ds3 it solves the problem.  Second being that
pings shows 17ms rather than 1ms I get when the static route is in place.  A
few have told me just to leave the static route in place but that seams half
assed to me.  If the ds3 is ever down then bgp would route around it.

Another problem, my providers upstream is global crossing and internap, on
gblx's route-server when my bgp session is down I see Cox's paths, but as
soon as I turn up bgp those paths disappear and gblx only shows the path
through me.  Not only that but gblx doesnt seam to listen either to the
route-maps and still sends traffic to my provider which also forwards it to
me.

I highly doubt my provider and gblx both have problems with there config so
I'm assuming it's my config or the router config at the other end of the
ds3.  Any advice?

Some of you may find info your looking for on my previous post at
https://puck.nether.net/pipermail/cisco-nsp/2005-July/022343.html


~Shaun





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