Able to ping but cannot browse after several hours running of my python program

It's a GUI program I wrote in python checking website/server status running on my XP SP3, multi threads are used to check different site/server. After several hours running, the program starts to get urlopen error timed out all the time, and this always happens right after a POST request from a server(not a certain one, might be A or B or C), and it's also not the first POST request causing the problem, normally 开发者_如何学Pythonafter several hours running and it happens to make a POST request at an unknown moment, all you get from then on is urlopen error timed out.

I'm still able to ping but cannot browse any site, once the program closed everything's fine. It's definitely the program causing this problem, well I just don't know how to debug/check what the problem is, also don't know if it's from OS side or my program wasting too many resources/connections(are you still able to ping when too many connections used?), would anybody please help me out?

Are you sure you are closing TCP sessions after each request? Try to check netstat information from time to time and if you'll see that the number of active/established sessions is rising it means that you have some problems in your script.

Yes, usually you can ping even if you are out of free TCP sockets.