On Thu, Feb 27, 2003 at 07:29:29PM -0800, David Barak wrote:
Nooooo!
eBGP multihop carries with it the implicit possiblity of session highjacking - in a normal (Multihop=1)
Everyone uses md5 signature/bgp password/ authentication keys correct? That means this isn't an issue :)
session, the router would not be able to find a duplicate neighbor with the specified IP address directly connected. Obviously, once you're saying that the neighbor could be anywhere in the world, what's to prevent me assigning my home Macintosh with a second IP address and injecting whatever I want into your network?
Second, Multihop is really a kludge: eBGP is ideally run at the edge of a network across a point-to-point (or shared) medium, and there really shouldn't be multiple paths to eBGP neighbors. If your link to ISP X goes away, do you really want to have your router think that ISP X is still available? Or would you rather just fail-over to a backup path?
iBGP is another matter -> there you want 255, b/c you want the sessions to stay up even in the event of a backbone link flap.
Depends on the size of the flap and router convergence times. - Jared