A customer with a new Dell PC, 3Gb ram and vista (this is the fastest vista I have seen so far… and its almost up to XP speeds…).

He had tried getting it to work with his wireless router (asus wl-520gc) and a belkin usb wireless adapter, but got nowhere (despite help from his ISP and the mob that sold him the pc).

Ok, I get there, knowing I had prior trouble with a vista wireless setup (vista cannot get dhcp address).

I start by getting the PC and the router and modem talking to each other with a wired ethernet connection. Although I don’t actually need to… I change the router IP address (and DHCP pool) so that they don’t conflict with the modem settings (the router has a WAN port, so I know the network on the modem side (WAN) will be isolated from the network on the PC side(LAN)). So the modem has the 192.168.1.X address range, and I give the router the 192.168.2.X address range. After all that, the internet connection works well.

Ok, now for the wireless: I do the usual: setup WPA-PSK, enter a “pass phrase” password, ask vista nicely to connect to the router, give it the pass phrase, and it connects correctly (after I miss-type a few pass phrases).

Ok, now to the final stage: I move the modem and router to main bedroom (so that there is no long telephone cable running down the corridor from the bedroom to the office)… and the PC refuses to connect with a “wireless association failed due to an unknown reason”.

I try some of the vista diagnostic and repair options, but none work. I try altering the router security settings, but find it only works with “open system” (no WEP encryption)… anything else fails… I make sure I alter the SSID with every change, in order to make sure I don’t connect to “leftover” WLANs (which XP is notorious prone to do).

After 2.5 hours, I decide to take the PC back to the workshop, and carefully try a few alternatives.

The owner doesn’t mind downgrading to XP, but I feel there is something to be discovered here, so I offer to fix it at no extra charge (I really want to know whats going on).

At the workshop, I try the PC with another wireless router (netgear dg834g)… and it works first time (with WPA encryption).

Ok, on the asus website, I see that the latest router firmware is 2.0.0.6 (the router is at 2.0.0.4). So I decide to upgrade the firmware.

I then try “open system” and it works.

I try wep, and it doesn’t…

I try restarting PC, router, and modem (power off everything), and then it works!

Ok, I setup the WPA settings in the router, and vista doesn’t connect.

I restart the vista, router, and modem… and vista can now connect!

I try restarting a few more times, and it works every single time. 

So where was the problem?

It could have been partially fixed by the firmware upgrade… but I’m starting to suspect that vista “tries too hard” to remember prior WLAN settings, such that changes in encryption will just not work without a reboot. And I also suspect something wrong with the asus wl-520gc wireless router as well.

So, from now on, if I’m working on vista wireless settings, I’ll make sure I restart vista and WAPs at every encryption change (what joy… most vistas i’ve worked with, are really slow to restart 🙁 )