SYN spoofing

Right, but ISPs can still filter on the corporate networks and at the
aggregation points for DSL and dial and any non-bgp customer. Those
talking BGP to you should be encouraged to do similarly. The full
thing is like next to impossible to maintain but doing these kinds of
relatively stady-state bits and pieces can help.

Wayne Bouchard wrote:

Right, but ISPs can still filter on the corporate networks and at the
aggregation points for DSL and dial and any non-bgp customer. Those
talking BGP to you should be encouraged to do similarly. The full
thing is like next to impossible to maintain but doing these kinds of
relatively stady-state bits and pieces can help.

And especially filtering out stuff like RFC 1918 source addresses and
such. That kind of thing should be possible on all routers (core and
edge) rather than adding to the pollution on the 'net.