Ok, first post from a long time (well since October when switched ) reader.. After having done a search and still not finding an answer to my problem I thought that I'd bite the bullet and actually post .

My problem is that since I picked up my new iPhone on Friday (yay!) I've been having issues with my home wifi network. I can't seem to access the internet wirelessly through my iphone, and now also my imac, which I've never had any issues with before. If I connect the Ethernet I don't have any problems, so I know that the modem is working fine.

I have also checked the router settings and can't find any problems there (although I really have no idea of what I"m looking at!) WEP has been entered correctly on both the iphone and imac. The only thing that I have noticed which seemed weird is that when I first tried connecting the phone to the network it showed an ip address starting with 169. instead of the usual 10. that I usually get and my imac is now showing the same in the TCP/IP settings.

I'm using a Siemens Speedstream 6520.. hoping that someone out there will have an answer.. oh and apologies if this isn't 100% clear, I'm not the best at trying to explain technical things...

Many thanks,

Angela

An IP address that starts with 169 is a self assigned IP, meaning that the network card thinks it has joined a network but can't get any addressing details.
Have you accidently joined you neighbours new wireless network?
Try turning off security for now on your router and setting a manual IP for the iMac and see how you go. From your post, I would guess that your iMac's manual address should be something like:

IP: 10.0.0.10
Subnet: 255.255.255.0
Router: 10.0.0.1
DNS: 10.0.0.1

Thank you for the quick reply. It works! and have just seen that the iphone has now connected too.
Thanks so much... now should I attempt to set up the security again? Our neighbors are a couple of hundred meters away, but I think that I should have some sort of protection set up, will that cause problems again. I suppose I should just try it

ok, have just tried re-enabling the WEP and won't let me connect. I don't know why this would only be starting now though, as I've had it running for months with no issues.. could it mean that my modem is on the way out? Oh well, will have to run with no WEP for now I suppose ..

Have you looked into using WPA, WPA-PSK?

Your device supports it, as well as WEP.

Somewhat correct, but technically it happens when the interface cannot find a DHCP server on the network its connected too. And as such this ip network range is used and an ip address is assigned from it.

It happens on all operating systems. Just part of one of the standards that everyone follows.

Thanks. I did see it listed under the security settings, I'm just not sure of how to set that up.

Pretty much the same as WEP. Choose WPA (or WPA-PSK if that is the option) and set a password.

just an update to say that I've successfully set up the WPA security and all is running great. Once again thanks to you all for you input