UPDATE: I have discovered that eth0 did not reset to half-duplex all of the time but only some times. Also, it occasionally appeared to have trouble resolving DNS.
Then, I connected the system in question directly to another host and assigned static IPs. Surprisingly, I got 100% success over 1,000+ pings. My next step was to bypass local router and switch and to connect Xubuntu system directly to the internet. Again, between 20th to 30th ping, packets started dropping out.
So I decided to try and spoof my MAC address and - lo and behold - I was able to sustain continuous ping both to the ISP's default gateway and to other hosts on the internet. I do not know if that has solved the problem, but just wanted to post an update. Still testing at this point. If anyone has any ideas please let me know.
ORIGINAL QUESTION: Up until a few days ago, my Xubuntu 14.04 worked just fine. Then I installed security updates and ethernet connection became problematic. It would initially connect just fine, but when doing a continuous ping to, let's say, google I got a staggering 20-70% packet loss. Likewise, browsing would either fail or took a long time to load any page. (Meanwhile, wifi connection still worked flawlessly.)
Google suggested this had to do with the NIC driver (r8169), so I downloaded and installed r8168 but the issue remained the same. Unable to find a viable solution, I restored a partition image prior to the update; apparently, it is now plagued with the same problem.
After further research, I ran ethtool and, sure enough, it showed that the NIC starts off in full-duplex mode, but defaults to half-duplex mode shortly after I start pinging. Forcing full-duplex and disabling auto-negotiation does not solve the issue. I had no success disabling IPv6, either.
Here's what I can say for sure - it is definitely NOT a hardware problem, because WIN7 gets a solid connection on the same NIC (the machine is dual-boot). Neither is it network related, because all other hosts on the same network get 100% connection as well. I even tried running a Xubuntu live CD but to no avail.
Can somebody please help me figure this out?
61 Answer
BLUF: If all else fails, try spoofing your MAC address and see what happens... :)
I've double checked everything since posting the update (see above), and couldn't find anything out of the ordinary. Meanwhile - knock on wood - ethernet works well with a fake MAC address. Hope this helps if someone else is having the same problem.
