I had totally the same problem. My "lspci" returns the same Davicom ethernet NIC. I followed the http://www.ubuntuforums.org/showthread.php?t=186430 and fixed the problem. It's great. I should have looked into ubuntu before I suspected my ethernet cable was failing. Thumb up to the ubuntu community. Who gave the fix? That person must be an excellent software design engineer in test.
-- Network interface ureliable in Dapper release-candidate https://launchpad.net/bugs/46822 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs