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Since a few days I have been noticing that I have some strange problems with my internet connection. I have not made any significant changes to the software / firewall settings / adapter settings on my computer (Windows 7) or the router+modem connecting me to the internet.

Description of the issues / additional info:

  • Trouble with establishing TCP connections (webpages often don't even start loading - but if they do [after numerous aborts/retrys] they load at normal speed)

  • Interrupted connections - Often, a webpage simply stops loading at about 50%

  • Most traffic-heavy programs seem to run fine (Skype, persistent Downloads, multiplayer video games work at the usual ping)

  • As long as the connection gets established properly, both ping and download rate seem to be as good as usual

  • Uploading seems to pose a problem (FTP client aborts connection mid-way, uploading forms in the browser often don't seem to work)

I run Windows 7, COMODO Firewall and use a Tilgin Vood Router/Modem.

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2 Answers 2

This sounds like a MTU problem.

Try to send bigger and bigger ping (starting at 500) until you see it fail to a known host, ex: www.google.com, and then verify your MTU is set to that "number just-befoer-it-fails + 28" value.

Ex: try 500, then 1500, then if it fails try 1000, etc: rapidly you'll find the best value by dichotomy (ie, separate the interval in 2, with lower bound ok and outer bound not-ok, until you reach the exact biggest OK value)

Example and details on : this page

Then change the MTU setting, and reboot your computer, and problem should go away.

(Could happen if you changed your local router, or if on the ISP side they changed something too)

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Try rebooting/resetting the router first.

If you have noticed these problems on other computers on your network, it's probably a problem with the router (or even ISP).

If not, it's a problem with your computer. Try disabling the firewall, just temporarily, and see if that fixes the problem.

This actually sounds like a bad DNS connection, so try configuring your router to connect to a different DNS server.

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