Can ping, network is up (netinst downloads packages) but once installed, DNS appears not to be resolving for browser, synaptic

I have a machine on which Ubuntu installs well. It has an atheros wifi card and a generic motherboard ethernet card.
I am trying to install Debian.
Debian of course does not recognise the atheros card, but I install with a wired connection.
The problem exists for both Edgy and current testing installs. The network install works so it is not a matter of missing packages.

After rebooting, I can ping for example www.cnn.com; this works.
But in Epiphany, I can not surf to any text URL (although IP addresses work);
Synaptic also fails to find any repositories.

Other machines work fine on the network, and Ubuntu 7.04 works immediately.

Back to Debian: I get the problem whether I use DHCP or static.
Manually entering DNS servers via the Gnone admin tool never seems to make persistent changes to resolv.conf
Disabling the network manager app at startup makes no difference.

It is weird that the network install works.

I don't even know where to begin looking to fix this, but I am not very experienced.

Update: lynx works. Disabling ipv6 in epiphany solves the problem in the browser.

regards

Tim