tcpdrop

I noticed tcpdrop(8) while tooling around with the latest FreeBSD 5.4 release. Example says it all:

If a connection to httpd(8) is causing congestion on a network link, on can drop the TCP session in charge:

# sockstat -c | grep httpd
www httpd 16525 3 tcp4 192.168.5.41:80 192.168.5.1:26747

The following command will drop the connection:

# tcpdrop 192.168.5.41 80 192.168.5.1 26747

Very, very cool. Would have come in handy early this week when two of my boxes were being flooded by a DDoS-like spam/virus email flood.