Ubuntu 7.10 DNS
After the upgrade, browsers, mail clients and other Internet-related applications run very slowly. Loading pages in Firefox can take 30+ seconds and sending/receiving emails seems interminable too.
On inspection, the Network settings seems to forget any custom settings (I had pointed it at the OpenDNS servers). Adding the OpenDNS servers to the router’s settings didn’t help. Re-adding the DNS servers to the Network Settings helped for about five minutes when it would once again lose the configuration and slow down.