This is the excellent idea! Actually, router vendors may simply add a feature which shuts down the interface if SYN/SYN-ACK balance is too bad -- thus disconnecting the hacker-to-be.

Of course, that balance may be decaying with time, so repeated unsuccessful attempts to connect won't trigger alarms.

--vadim

Ah, that's fun if it's a XP interface we're talking about :) Presumably you wouldn't enable that option on one, though... Avi

Forrest W. Christian <forrestc@iMach.com> wrote:

Maybe I'm missing something here, but wouldn't these Denial of Service attacks cause a severe mismatch in the numbers of SYNs and SYN-ACKs on a given router interface?

If so, then couldn't we just sweet-talk cisco into providing 5 minute counts of syns and syn-acks on an interface?