[SOLVED] Ethernet hangs up with Realtek RTL8111/8168B, r8168 doesn't help

[kalbelo]

I have a Realtek wireless card and faced a very similar problem.
for my case, the problem was intermittent and frequently the system was able to identify the SSID of the Acess Point but get problem during the authentication or IP addr obtaining processes. The pinging looked like yours.
Considering that the issue happened on my Fedora and Win XP as well both using the same Realtek card, I started to play with the antennas of the card (the card is a PCI based, not a laptop like you) and then I got success for the connections
Unfortunately I didn't get a step by step how to solve that.

[grassmaster]

Sadly the issues I'm having are present with my ethernet NIC too, so there's no chance for a bad antenna setting. Moreover, when I was testing wireless connections, I was sitting a few feet from my router and still it was behaving badly (as with the cable).

Anyways, thank you for your input, kalbelo

[grassmaster]

It has turned out that the router was the culprit. I have solved the problem by replacing the router by a new one (by TP-Link).

Anyway, thanks everyone for the replies.