A customer cannot get broadband (housing compound uses a PABX), but wants to have 2 PCs share the dialup internet link (without any messy wires). He also wants me to look into a few other things, most of which are easy to do, so I do them while setting up the wireless network.

After some thought, I decide the best solution is to setup an ad-hoc 802.11G connection (both PCs run XP). I setup a pci wireless card in one PC, and a USB wireless card in the other (both are generic chinese cards – FAST).

After some hiccups (cannot install pci card into the PC that has all PCI slots used 🙁 ), I get the usb ‘card’ working well (I setup WPA-PSK with very little problem). But the other PC (with PCI card), behaves very strangely: The software won’t allow me to setup both WPA and ad-hoc.

I try installing a different set of software (the CD has 2 to choose from)… but no luck…

I run out of time, so I make an appointment to return 2 days later.

I do some research and eventually it dawns on me: I’ve seen this before: both PCs must be running SP2 in order to use wireless networks correctly!

So when I return, I install SP2 and try it again… the software works better, but I still cannot use IBSS and WPA at the same time!

I decide that its probably not possible to use WPA and IBSS at the same time (although nothing on the net seems to indicate that the 2 are incompatible). So I fall back to WEP, and that works better… I see green bars, which indicate a wireless link has been established.

I do a ping test, but I get no response… Hmmm… why?

I ping from both computers, but no success. I change ‘automatically obtain IP address’ to a fixed IP address, but still no luck.

I disable the windows firewall, and then the ping works. I’ve not seen the windows firewall prevent LAN pings before!

Anyway, it works, so I re-enable the XP firewall, and I look at setting up a bridged network (as per my previous post: another visit to the vet ), but it won’t work… xp insists that I use internet connection sharing… it only wants to bridge non-dialup networks. I figure: ok if it wants to do it like that, I’ll do it.

I setup ICS on the modem PC, then I do what XP recommends (let the second PC get its IP address automatically).

I dialup the net, then bring up a web page, then I go to the second PC & I can also view a web page: success!

The modem PC starts downloading a windows update, and I also start an antivir and spywareBlaster update… it will take a while, but I have achieved most of what I set out to do.

The only thing that I  couldn’t do was speedup his 1Ghz celeron PC. It ran unusually slow, and DVD playback would invariably result in stuttering audio and video. Diagnosis would be expensive, as would a windows reinstall with a full backup, so the customer will leave it for now.