I use a LAN chat client called BORGChat. Its a very good piece of work. Although its a windows program, I run it in linux with WINE.
Getting BorgChat to work through firestarter was a bit of a problem, but I managed to figure it out. First, I found out which ports borgchat uses. This can be done in two ways:
1) Open BorgChat, go to "Options > Connections" and it will show you the post
2) Disable the firewall, run BorgChat. now open a terminal, and type sudo lsof -Pni . Now look for Borgchat and Wine. You will find the ports on which they are listening.
Once you know the ports, you have to open these ports in Firestarter. I allowed only Local users to access, by using 10.10.19.152/255.255.255.128 (ip-address/subnet-mask) in the "allowed" section.
But borg was still not working. Then, I went to "Options > Connections" in BorgChat again, and selected the method IP multicast instead of UDP broadcast. And then I told my friend on LAN to do the same. Borgchat then started running normally. I can even transfer files.
The obvious drawback of this method is that you'll have to tell all people on the LAN to use IP Multicast. I have only one friend on LAN, whom I chat with, so it was not a problem for me.
If, by chance, Borg is still not working for you, then you may need to follow the steps in my previous post (Firestarter and Samba).