I have a dual-boot machine: Windows 7 and Ubuntu 10.04. The computer is connected directly to the Baudtec modem by a LAN cable. The modem is connected to the phone jack. Under Windows, the internet works without any problems.
Under Ubuntu, I set up by using pppoeconf and can get online without a problem. However, after some time (about 15-20 minutes, sometimes less), the internet stops working. That is, I cannot open any website. I can still "ping 188.8.131.52", although "ping www.google.com" says "unknown host". Also, if I have gmail open in the browser, it may continue to work for some time, though I cannot load any other site. Also, my ISP continues to see me online, so there is no problem from their point of view.
The following commands do not help to restore the full connection:
pkill -9 pppd
However, they do help after powering off the modem, waiting for a little while and turning it back on again. I exchanged the modem (Baudec is the current one), but the problem persisted.
Please let me know what information I may provide to help diagnose the problem. I will very much appreciate your help.
Thanks to the first reply, I found a much easier way to restore connection after a crash. Namely, I noticed that after doing "ping 184.108.40.206", I can ping my provider (i.e. the IPs in the /etc/resolv.conf before the crash) as well. So, I just do "ping 220.127.116.11" and restore /etc/resolv.conf from a backup copy and the internet works again! I do not even have to restart pppd. After some 20 minutes the problem repeats itself...