Websites only loading after second refresh

[Segmented]

Hi

We've got a strange problem with out Internet where pages only seem to load after you press refresh in the browser when viewing for the first time. Our setup is a Netgear DG834 which is setup to DHCP for the network. I've tried pinging domain names from command prompt and they seem to be resolving first time, but when using the web (via firefox) it seems we have to hit refresh and then the page loads. The router is running the latest firmware and all DNS settings are automatic from our ISP. Has anyone come across this problem before?

Thanks a lot for your help

 

[Segmented]

It's happening across the network. Just tested in IE7 and everything seems fine, but this could be because the DNS is now cached. I tried some sites I haven't visited in a while in IE and it seems ok. Could this be a problem with Firefox? We're using 2.0.0.3

 

[Segmented]

Who is your ISP? Perhaps they are running a transparent proxy which is malfunctioning?

I'm with Clara net. That's strange actually, as I've had a proxy error message appear a couple of time when accessing one of our sites hosted on their server. I know that is hosting and this is dsl, but could they be related?
Thanks