Well, I finally got to the bottom of it. There seems to be a bug in the DLink G604T router doing DNS under some circumstances. Even after a firmware upgrade.
I got tcpdump out to look what was happening and saw some very strange things. For instance, an ftp request to ftp.nl.debian.org was actually going to 192.168.1.1, which is the router itself! I then pinged the debian domain, and saw the pings going to the router too. Bizarrely, when I opened ftp://ftp.nl.debian.org in a browser, it came up just fine, and a connection from the command line then started working too. It looks as if the DNS relay service on the router caches info in some way, but doesn't keep the cache clean. Or something. Anyhow, it's broke. Anyhow, turning OFF the DNS relay and setting up DNS in /etc/resolv.conf fixed all this stuff. I had tried this before, but it didn't work - maybe because I was still using DHCP. With DHCP, /etc/resolv.conf gets overwritten after a reboot to the router address. Plus this is the first time I have configd a network, so I guess I was just on a learning curve. So, if you are suffering from similar problems and use a Dlink router: 1. set all your PCs up with statically defined ip addresses. 2. turn off DHCP in teh router and manually add the IPs for your PCs there. 3. Look in the router logs to see what DNS settings it was getting from your ISP, write them down and manually configure that on all your boxes. 4. Turn off DNS relay on the DLink. (What is that for, anyway?) thanks to all who helped Daniel -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]