Trying to play with my son online

[Taem]

I got a reply on The Dark forums which progressed me a bit further, however I'm still running into difficulties (see below):

Try using a local area network (LAN). It takes some tinkering with the net settings (the IPX protocol has to be enabled, I forgot how I did that), but the results are wonderful. Excellent speed and never a dropout. This can be achieved with one or more computers connected to the same router, and even with PC's hooked to the ADSL modem.

I googled "IPX protocol Diablo" and got a whole walk-thru on enabling IPX for your LAN network, so I did that. The next problem is apparently both computers need to be hooked up directly via Ethernet wires for this to work (i.e. computer to computer through the network cards). I think the way you must have got them to work together is perhaps through file-sharing? I don't know... I can't seem to find out anything else so far.

I finally got an idea however: there are 3-unsecured wireless networks around here, so I set up my sons computer to another wireless network that isn't mine and volia, we can now play via Kali, however whenever we try playing on Battle.net, it still says, "Cannot connect due to high latency" or something like that. My friends son wants to play with us online too, but can't afford Kali so B.net would be ideal. Any idea why B.net is still giving me this latency error?