Sometimes access to internet stops being available
I haven't been able to figure out what causes the problem. Sometimes i think it's because i have so many "internet applications" open (like firefox + pidgin + transmission + skype + teamviewer...). All of the sudden, all internet access becomes unavailable. I cannot access any internet services; If i try to ping a server, it says "unknown host"; Pinging my router works fine.
After reboot, it's okay again.
But it's not because of the IP change for sure, because this problem can happen any number of times during the day and it doesn't start working again no matter how long i wait (until i reboot).
Sometimes i try to narrow down to see if it's one specific application, but no obvious pattern is to be seen. Altho that thought seems to be on the right track, because when i only use Firefox, it never-ever happens.
Also, it doesn't happen immediately after i open an application (obviously, otherwise i'd be able to figure out which application it was). Today it happened after having transmission opened for like 20 minutes, last time it happened was like a month ago.
Restarting /etc/init.d/networking does not help, rebooting the computer does. What can i try that would narrow down on the cause of the problem? Is there some log file where i could check for errors or something?
I'm using Ubuntu 10.10 and Gnome 2.30.2