Ok I'm pulling my hair out over this one. We have a wireless network with many clients all working well except two Ubuntu clients running 10.10 that can't access the internet via a browser at the same time. They can both still ping, use Skype etc but can't browse.

As soon as the one that can browse exits the network browsing returns for the other and vice versa. As ping and Skype was working I assumed some kind of DNS problem but moving over to OpenDNS didn't solve it, nor did restarting networking or using wired rather than wireless.

We also switched out the router, and it still persisted so I'm sure this isn't a network issue. The two clients are both laptops and work fine together on a wireless network at another office (which we don't control).

I'm thinking something must be cached from the other network they both use that's causing this but have no idea what.

Does anyone have any ideas? I just don't know where to go from here.