The fifth and final tab in the Peekko Chat Options is Advanced. I strongly suggest you leave these settings alone, unless you are experienced with IRC-based chat clients.
If you do fancy yourself a bit of an IRC veteran, you can modify the server you would like Peekko to connect to as well as the port number. In addition, you can also specify the amount of seconds you would like to attempt your connection prior to timing out.
Please keep in mind that Peekko is still technically a beta client, although it is widely distributed and used. Also, it is not really meant at the moment to be used to access IRC servers other than Peekko's chat server itself. If you wish to ignore these warnings and venture out to other servers with this extension, proceed at your own risk.
