I checked the BT HomeHub and the broadband light and LAN lights were on but I rebooted the hub just for good measure.

I then connected my iPhone to the hub via wi-fi and it was instantly online so no problem with the broadband connection itself and access to google.com and hotmail.com was fine.

The ethernet cable from the router to the computer was seated correctly, the XP machine had picked up an IP properly from the router’s DHCP, it all seemed ok.

I tried accessing bbc.co.uk just in case it was a caching error and to my surprise it loaded the page without delay.  After trying a few others, skynews.com, digg.com, etc I established it was just a handful of sites affected.

Rather than the usual, “just give it a reboot” I wanted to see if I could find a fix without restarting. Since almost all site except ones used regularly on that machine were working it had to be some sort of DNS or cacheing issue. I’d tried emptying internet explorer’s cache and relaunching IE7 which had not effect. I then found firefox hiding on the system and never used so I tried that and same problem, so it wasn’t a program specific cache it was a global cache somewhere on the machine and there appeared to be a very easy fix, just clearing the local DNS cache from the command prompt.

Simply open up a command prompt window (windows key+R, then type “cmd” and hit return). Once in command prompt just type:

ipconfig /flushdns

This will clear any local DNS cache which Windows XP has created to speed up access to some sites you have recently visited. After flushing the DNS Internet Explorer opened google.com and MSN Live messenger signed in without a hitch and no need to restart either You can edit your Windows registry and set the local DNS to never cache or have a much shorter cache refresh period but I didn’t bother in this case.

I know this is common knowledge to a lot of people but it should serve as warning when testing for an internet connection, don’t simply try to access google.com, or some other well known site that may be in a corrupt local dns cache. It’s the first time I’ve been caught out by it and it’ll certainly be my last.

Well having successfully updated my iPhone to 1.1.3 I have noticed that I am no longer able to join wi-fi networks, it says i’m connected to my Apple Airport but browsing web pages fails stating unable to connect to server.

I jumped into settings and turned wi-fi off then back on and let it join the network again. Same problem.

I then tried the advanced tab for the network and told it to forget the network and then find it again, same problem.

I tried force closing Safari (by holding down the home button) and then relaunched Safari, still not working.

Next was to reboot the airport express, didn’t solve it.

I tried my MacBook Pro on wi-fi, worked ok so it’s not an internet or airport problem.

Finally I noticed in the advanced tab of the wi-fi network that the phone was getting a self assigned IP address (169.xxx.xxx.xxx) not picking one up from Airport DHCP. Clicking renew lease didn’t work, still self assigned IP so this appeared to be the problem, the iPhone wasn’t being assigned an IP by my airport express. I tried my netgear (Sky) router and the same problem with that.

I finally turned the phone off and back on (with a forced reboot, holding down home button and power button for up to 10 seconds) and then checked the wi-fi advanced page, finally it picked up a DHCP assigned IP and all is well again.

Not sure what 1.1.3 did but I’d never had that problem before.

On a side note: a family member also has an iPhone and updated to 1.1.3 last night. He said it all went well, he was playing with the new features before he went to bed and then turned his phone off last night. On the way to work he powered his phone back on and it’s simply showing an icon saying connect the phone to iTunes, emergency calls only. So it looks like its gone back to the “virginal” or “as new” setting for some reason. So he’s without his phone and all his contacts until he gets back from work.

UPDATE: Two friends updated their iPhones to 1.1.3 and neither could then connect to wifi (Apple Airport or their Orange Livebox Router). Same problem with it not picking up an IP via DCHP. They gave me a call so I pointed towards this blog to follow the instructions. They both followed all the steps above and this worked for one of them only. The other iPhone still wouldn’t pick up an IP. In the end he fixed it by simply going into the settings menu and choosing

“Settings”->”General”->”Reset”->”Reset Network Settings”

so you might want to try that first as a quicker and easier fix?