Tag Archives: ad-hoc

Cannot discover wireless networks (ad-hoc problem)

Computer Aid Posted on by

I supplied a new PC to a customer.

He was retired, so he saved some money by getting his son to install a corporate XP.

But once he got it back, he couldn’t get the wireless internet link working.

So I pop over, enter the WEP details (the wireless router had been setup a long time ago, so I didn’t want to go change it).

But no matter what I tried, I just couldn’t see any networks to connect to.

So, I figure I haven’t much choice, I’ll need to connect directly to the router via ethernet, and setup a WPA network… I’ve developed a strong dislike for WEP.

So I setup the WPA-PSK settings in the router, reboot, and so far I can see the router.

I disconnect the ethernet cable, but when I try to connect to the wireless network, it just fails silently. No error messages, and no indication that there is a problem.

I check that XP is managing the wireless network connection, DHCP is running correctly, but after looking at countless wireless networks, this one doesn’t want to work properly.

So I find myself doing what I often do in this situation: I start to aimlessly browse the network settings.

Thats when I stumble across the cause:

In the “wireless network connection properties”, click on the “wireless networks” tab, and then click on the advanced button (not the advanced tab, the button near the bottom of the window).

And up pops a seldom used “networks to access” window.

Ordinarily, its set to “any available network”. If I’m setting up XP, I usually change it to “infrastructure networks only”… but in this case, it was set to “ad hoc networks only”.

Obviously there are people out there who still use ad hoc networks (I can’t see the point anymore. It was a useful a when access points were much more expensive, but not anymore).

ad-hoc (IBSS) wireless network, WPA, and XP SP1

Computer Aid Posted on by

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.