Kill SSH tunnel?

I’m doing the following to create an SSH tunnel:

ssh -fNg -L 8888: user@123.456.789.0

How can sort of “undo” that? I ask because I need to re-tunnel in to a different IP address but right now the only way I can figure to do it is to restart my computer (which is lame).


ps -ax

to determine process id. And then use

kill process_id