problem with BGP or I am an Idiot

To all,

Probabaly the the latter; however here is the situation. I am advertising a rte 1.1.1.1 via BGP to the Internet via ISP_A via my location in NJ. At my other location in CA where I am advertising another rte 2.2.2.2 via BGP to the Internet via the same ISP_A. I am using the same AS for both routes.

For some reason on my rtr advertising the 2.2.2.2 rte I am unable to see the 1.1.1.1 rte "% Network not in table". I know 1.1.1.1 rte is valid it shows up in looking glass and ISP_A has it on the peer 2.2.2.2 recevies full Internet rtes from. Further verification: I add a static rte on 2.2.2.2 rtr to 1.1.1.1 and its routable???

How is this possible? I have the following filters but I removed them and it seems to not make a diff.
OUTBOUND - ip as-path access-list 1 permit ^$
                     ip as-path access-list 1 deny .*
INBOUND - ip as-path access-list 2 permit .*

Philip

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Philip Lavine wrote:

To all,

Probabaly the the latter; however here is the situation. I am advertising a rte 1.1.1.1 via BGP to the Internet via ISP_A via my location in NJ. At my other location in CA where I am advertising another rte 2.2.2.2 via BGP to the Internet via the same ISP_A. I am using the same AS for both routes.

For some reason on my rtr advertising the 2.2.2.2 rte I am unable to see the 1.1.1.1 rte "% Network not in table". I know 1.1.1.1 rte is valid it shows up in looking glass and ISP_A has it on the peer 2.2.2.2 recevies full Internet rtes from. Further verification: I add a static rte on 2.2.2.2 rtr to 1.1.1.1 and its routable???

How is this possible? I have the following filters but I removed them and it seems to not make a diff.
OUTBOUND - ip as-path access-list 1 permit ^$
                     ip as-path access-list 1 deny .*
INBOUND - ip as-path access-list 2 permit .*

Loop protection. Throw away any route I hear from someone else with my AS.

- --

As long as you are hearing default your transit providers (you do have at least two, right? if you only have one, you don't need BGP and are just polluting the routing table), it won't matter if you can hear the prefix from your other location.

you will not accept a route with your AS in teh path

you can override it (on cisco) with allow-own-as

Steve

Philip Lavine wrote:

To all,

Probabaly the the latter; however here is the situation. I am advertising a rte 1.1.1.1 via BGP to the Internet via ISP_A via my location in NJ. At my other location in CA where I am advertising another rte 2.2.2.2 via BGP to the Internet via the same ISP_A. I am using the same AS for both routes.

Don't do that then.

For some reason on my rtr advertising the 2.2.2.2 rte I am unable to see the 1.1.1.1 rte "% Network not in table". I know 1.1.1.1 rte is valid it shows up in looking glass and ISP_A has it on the peer 2.2.2.2 recevies full Internet rtes from. Further verification: I add a static rte on 2.2.2.2 rtr to 1.1.1.1 and its routable???

The reason is that a BGP router won't accept a route containing its own AS from an external peer.

You can add a static route on both routers to the other network with the gateway of your ISP. A floating static default may also work. Or get a different AS for the other end.

Date: Fri, 17 Nov 2006 15:56:53 +0000
From: Stephen Wilcox

you can override it (on cisco) with allow-own-as

s/allow-own-as/allowas-in/

Eddy