If it's just the two of you having a bash about, there is an easier way
First, get your friend to go to http://www.whatismyipaddress.com
before he starts JO.
Then, over your IM prog (or e-mail), get him to tell you his IP address.
Once he's got his game running, start yours and bring the console down and type \connect 12.345.67.890
Obviously, change the number for your friends IP address
Your computer will connect to his (or vice versa if you want to host) and you can enjoy kicking the living carp out of each other, laming, swearing and spamming red DFAs without the restrictions you face on a regular server.
Like me and BawBag