Indeed. For instance SYN-flood the BGP port.
Correct me if I'm wrong but to the best of my recollection, in order for a packet to be accepted on the BGP port, it must be originating from a configured BGP peer. Since the SYN flood method relies on the attack originating from an unreachable (yet routable) address, it would seem that this approach will fail. If you're out for a true DoS attack, it need not even be a SYN attack. Simply flooding the BGP port would be quite enough to bring the system to its knees. Forge a known peer's source address, and even the CPU that it burns testing for authentication and discarding packets would be enough to be fatal. The important point is that you can't distinguish the good from the bad without a whole lot of work. Tony