How to kill a TCP connection using tcpkill utility
For tcpkill to work (i.e., craft a reset packet that has the correct sequence number and source port), there must be traffic. If nothing more is printed then there is no traffic. To verify you could run
tcpdump -i eth1 port 443.
I had to kill an established connection on which there was no traffic (a debug session on a JVM).
tcpkill as explained in @Mark Wagner answer could not do it, however
killcx 1.0.3 (link) did (Ubuntu 10.04).
It is a perl script that has a dependency on a few libraries.
On a connection that could not be killed with
killcx the combination of both
killcx did it:
Say the connection if from
- In a terminal start tcpkill:
tcpkill port PORTL. Tcpkill will start listening for traffic
- In a second terminal launch killcx: