[c-nsp] prefix-list/route-map quandry
Ian Dickinson
iand at eng.pipex.net
Tue Feb 7 03:43:38 EST 2006
You're matching and accepting the default route, but the implicit
deny on the end of the route-map is killing the customer routes.
Simple fix is to add the following and you'll be sorted.
route-map he-def-prepend permit 100
There are many other approaches to this too.
Ian
Charles Sporkman wrote:
> Hello,
>
> I'm getting a little bit stuck here. I spent the better part of
> friday evening looking at the "IOS Essentials for ISPs" book and at
> the resulting config and just walked away scratching my head...
>
> What I want to do seems pretty simple (I think). I have two
> upstreams. No problems with announcing my prefixes, everything's
> fine. Inbound, they are both giving me default, and one "ISP X" is
> giving me customer routes as well. "ISP Y" is my preferred provider.
> I want to use "ISP X" for:
>
> -backup if I lose "ISP Y"
> -I want to send any traffic destined to their customers to them directly
>
> So in essence, I want to pad the incoming default route from them, but
> not the customer routes. I'm doing the following right now, and not
> seeing any customer routes in the table (but they are being received
> according to "sh ip bgp x.x.x.x"):
>
> neighbor 10.1.1.2 remote-as 6939
> neighbor 10.1.1.2 description Hurricane Electric
> neighbor 10.1.1.2 password <removed>
> neighbor 10.1.1.2 update-source Loopback0
> neighbor 10.1.1.2 version 4
> neighbor 10.1.1.2 soft-reconfiguration inbound
> neighbor 10.1.1.2 prefix-list bgp-out out
> neighbor 10.1.1.2 route-map he-def-prepend in
> neighbor 10.1.1.2 route-map prepend-us out
> !
> ip prefix-list he-match-def permit 0.0.0.0/0
> !
> route-map he-def-prepend permit 1
> description prepend on default route only
> match ip address prefix-list he-match-def
> set as-path prepend 6939
> !
>
> I'm totally new to prefix-lists, somewhat rusty with route maps, and
> pretty much lost on using them together. What's gone awry here? The
> rule is working as far as prepending an extra hop on the received
> default, but the other routes are not showing up anywhere. As you can
> see, I currently have no inbound filters (yes, I don't want to do that
> permanently)...
>
> Just so we can all see that I am hearing their routes:
>
> router#sh ip route 216.218.186.0
> % Network not in table
> router#sh ip bgp 216.218.186.0
> BGP routing table entry for 216.218.128.0/17, version 1868955
> Paths: (1 available, no best path)
> Not advertised to any peer
> 6939, (received-only) <<---
> 209.51.171.25 from 209.51.171.25 (216.66.23.98)
> Origin IGP, metric 1, localpref 100, valid, external
>
> I'm probably doing something really stupid and blaming it on the route
> map. Just not sure what I'm doing that would stop the received
> routes...
>
> Thanks,
>
> Charles
--
Ian Dickinson
Development Engineer
PIPEX
ian.dickinson at pipex.net
http://www.pipex.net
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