http://grc.com/dos/grcdos.htm
A Quick & Easy Check for IRC Zombie/Bots
If you have managed to read all the way through this lengthy and detailed adventure, I am sure you will agree that you do NOT want any of these nasty Zombies or their relatives running around loose inside your PC. Fortunately, it's quite easy to verify that your system is not currently infected by one of these IRC Zombie/Bots.
All of the IRC Zombie/Bots open and maintain static connections to remote IRC chat servers whenever the host PC is connected to the Internet. Although it is possible for an IRC chat server to be configured to run on a port other than "6667", every instance I have seen has used the IRC default port of "6667".
Consequently, an active connection to an IRC server can be detected with the following command:
netstat -an | find ":6667"
Open an MS-DOS Prompt window and type the command line above, then press the "Enter" key. If a line resembling the one shown below is NOT displayed, your computer does not have an open connection to an IRC server running on the standard IRC port. If, however, you see something like this:
TCP 192.168.1.101:1026 70.13.215.89:6667 ESTABLISHED
. . . then the only question remaining is how quickly you can disconnect your PC from the Internet!
A second and equally useful test can also be performed. Since IRC servers generally require the presence of an "Ident" server on the client machine, IRC clients almost always include a local "Ident server" to keep the remote IRC server happy. Every one of the Zombie/Bots I have examined does this. Therefore, the detection of an Ident server running in your machine would be another good cause for alarm. To quickly check for an Ident server, type the following command at an MS-DOS Prompt:
netstat -an | find ":113 "
As before, a blank line indicates that there is no Ident server running on the default Ident port of "113". (Note the "space" after the 113 and before the closing double-quote.) If, however, you see something like this:
TCP 0.0.0.0:113 0.0.0.0:0 LISTENING
. . . then it's probably time to pull the plug on your cable-modem!
Note that a Windows IRC client program running in the PC will generate false-positive reports since these are tests for IRC client programs. So be sure to completely exit from any known IRC client programs BEFORE performing the tests above.