Beyond of this, tor also open a tunnel on the firewall. Suppose you live in irc.freenode.net but the port 6667 is blocked by the firewall. You can torify irssi to using the hidden service, and keep you IP private, — one stone kills two birds!
Add this line to /etc/tor/torrc
mapaddress 10.40.40.40 mejokbp2brhw4omd.onion
Run irssi in torified mode:
conn 10.40.40.40 to access irc.freenode.net. If you don’t have the
privilege to access /etc/tor/torrc, you need
socat to relay the tor network to your
local socket proxy:
socat TCP4-LISTEN:6667,fork SOCKS4A:localhost:6ua4nhltph56henu.onion:6667,socksport=9050
Then you can run
There is a more detailed HOWTO about the onion router.