Will this default route 0.0.0.0/0 be exporting to AS-level neighbors? On Mon, Jan 5, 2009 at 8:49 PM, Edward B. DREGER <eddy+public+spam@noc.everquick.net> wrote:

KC> Date: Mon, 5 Jan 2009 18:05:48 -0600 KC> From: Kai Chen

KC> is this router using a default routing for all the other KC> destinations?

Either that:

router> sh ip route 0.0.0.0 Routing entry for 0.0.0.0/0, supernet

or partial tables with no default:

router> sh ip route 0.0.0.0 % Network not in table

is what you'd expect.

Eddy -- Everquick Internet - http://www.everquick.net/ A division of Brotsman & Dreger, Inc. - http://www.brotsman.com/ Bandwidth, consulting, e-commerce, hosting, and network building Phone: +1 785 865 5885 Lawrence and [inter]national Phone: +1 316 794 8922 Wichita ________________________________________________________________________ DO NOT send mail to the following addresses: davidc@brics.com -*- jfconmaapaq@intc.net -*- sam@everquick.net Sending mail to spambait addresses is a great way to get blocked. Ditto for broken OOO autoresponders and foolish AV software backscatter.

cK> Date: Tue, 6 Jan 2009 07:40:16 -0500 (EST) cK> From: chloe K cK> Why it needs default routes when running BGP? If you have a full table, you do not need default. It's even desirable to drop road-to-nowhere packets inside your network, before they clog up your connections. However, consider that you may encounter some problems -- such as insufficient RAM to deal with growing table size -- that leave you forced to take a partial table. Then what? If you're running BGP, you probably have more than one upstream, so you don't want static defaults (unless the next hop is a serial interface). To deal with this, you can have your providers originate default _and_ send a full table. Under normal circumstances, use a route map that nukes 0/0. If you find yourself in a jam, replace the route map with one that allows 0/0 and discard long paths, AS_PATHs that you consider troublesome, et cetera. You still have the benefit of directing certain routes to a specific provider, but with a smaller (partial) table. Finally, note that not every router needs full tables. Consider a peering router that exchanges traffic between a network's peers and customers. Eddy -- Everquick Internet - http://www.everquick.net/ A division of Brotsman & Dreger, Inc. - http://www.brotsman.com/ Bandwidth, consulting, e-commerce, hosting, and network building Phone: +1 785 865 5885 Lawrence and [inter]national Phone: +1 316 794 8922 Wichita ________________________________________________________________________ DO NOT send mail to the following addresses: davidc@brics.com -*- jfconmaapaq@intc.net -*- sam@everquick.net Sending mail to spambait addresses is a great way to get blocked. Ditto for broken OOO autoresponders and foolish AV software backscatter.