Hi.

My main Debian machine seems to have developed an unusual problem today with its internet. After booting up Debian (7 Wheezy) and browsing the Web for a little, the Internet connection fails in that it gets caught "Waiting for <site name>..." and Iceweasel times out with a "The connection to the server was reset" (or something like that) message, no matter what site is tried. If I try using another program to go online with, it might work for some time, then fail, e.g. if I try to download packages with the package manager, it works a little, then quits. Rebooting allows it to work for a little while, then it stops again. ALl the time, I can ping remote sites. I didn't change anything during the day, and it was going along fine for a while and failed. I have tried looking at ifconfig and route, netstat, network card seems to work OK, routing seems OK (I'd expect the pings to fail to get through if it weren't) it's just that the Internet connection is having this trouble. Other computers in my home on the same network are unaffected -- their Internet is just fine. That and the fact that reboots briefly stop it appears to suggest the problem is on my end, not the ISP's end.

What should I do to troubleshoot it? Thanks.

A couple of ideas you may have tried already. Replace the ethernet cable, if you are using one. Try plugging your ethernet cable into a different spot on the router/modem. Also reboot the modems and router and see if that helps at all. If you can try plugging your internet, briefly since others are using it, straight into the modem, not the router, reboot (unplug and plug it back in,) the modem and see if you still have the same issue or not. If you tried all of the above than it has to do with your PC or Debian configuration.

Also. If you have heavy traffic sharing the same internet connection that may be slowling things down majorily for you at times.

Odd. Apparently, as mysteriously as it started, the problem seems to have stopped... for now. So I can't troubleshoot it anymore... as it's just gone.

are you using static IP?
iirc, I had similar problem, network manager or similar package in Debian would automaticaly wipe static DNS settings and try DHCP.

Dear mike4ty4,
Not quite sure, but try to see last lines of `dmesg` command in a terminal, just after problem happens. May be it may give you some indication of problem.

e.g. in my case I use a usb phone modem, which also sometimes behave as you said.
Replugging my modem solves the problem.