Sigh. My feeling is that host-based solutions should be discussed
on inet-access, but mentioned briefly also on nanog so that providers
can note them to give pointers to their customers.
And there probably is too much SYN-related traffic on nanog anyway.
The plea has been made: You should - or you should encourage your
customers to - filter garbage inbound to you from them or outbound from
them to you. You should come up with a plan to nail the source of
SYN attacks quickly if the trail leads to your network as the source.