Date: Wed, 12 Jul 2000 08:26:56 -0400 From: "HANSEN CHAN" <hansen.chan@alcatel.com> Sender: owner-nanog@merit.edu
Hi folks,
I understand that MD5 is quite commonly used in IGP such as OSPF but not in BGP4. Am I correct? Can someone explain to me why? Shouldn't one be more concerned the session being hijacked when talking to another network?
I'll take a crack at this, I guess. OSPF and most (all?) other IP based routing protocols broadcast and flood data. This make it pretty easy for someone to simply send out a spoofed packet and have it believed by on or more routers. BGP is a TCP based protocol and is normally run only to an adjacent peer. This combination makes it very hard to break into. You have to have another system on the shared media send a spoofed packet with bogus information that fits the TCP stream and the BGP status for that peering (and many BGP connections are point-to-point, making even this impossible). Multi-hop BGP is a different beast and much more likely to be subject to attack, but it's also pretty rare and such an attack would still be very difficult. R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634