Just upgraded a Ubuntu 9 server to 10.04LTS and have a problem I can't get my head around. Basically I can't get a two way dialog going with the internet ie can't browse (using lynx) or get a file content using php. However I can SSH from server to a remote server and also SSH to my server from the remote. Ditto with ping (both IP address and canonical, so DNS is OK). I can access apache on my server from remote.
When I start lynx it usually fails with a timeout and Unable to connect to remote host message, but just occasionally can get a reply from lynx.isc.org.
Any suggestions for further tests etc?