Edge BGP Router as Default Gateway

It seems normal to me. The default gateway is usually the router that connects to the Internet.

In our scenario we have backup transit through another AS. If our BGP router fails how would we maintain a default gateway. I can see how traffic would still reach us from outside, but how would internal machines get outside as the D/Gateway would be gone. Could we HSRP the gateway IP to the backup transit provider assuming they agree?

Gary

On 05.11.2005 02:57 Barry Margolin wrote

I wouldn't characterize a default gateway that way, but having internal servers point default to an edge BGP router *may* be Ok. That much depends on the topology of your network.

Imho a default router is a router which has better knowledge of the internal network than a server. In small networks this router may also connect to the Internet, in bigger one it doesn't.

ymmv, Arnold

On 05.11.2005 06:26 Gary wrote

A much better design is to have two routers speaking HSRP/VRRP internally. Both talking BGP to outside as well as iBGP to each other. One is connected to your upstream, the other to your backup.

Arnold

Two critical considerations will influence where you assign the default gateway. Availability concerns could dictate multiple routers on the internal network serving as one or more logical default gateways using HSRP or VRRP. Security concerns could dictate firewalls between your BGP speaking outside routers and your internal networks, so your default gateway could be the firewall or internal router(s).

Good luck and have fun!

When you said "*the* edge BGP router", I interpreted that as meaning that there was just one. If you have other edge routers, like the one connected to the backup AS, then that changes things.