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I cannot visit several websites, they just keep loading forever until the connection attempt times out. I am sure the websites are running fine because I have no problem accessing them through proxy servers. This happens on all computers in my network regardless of operating system. I was able to find out that some websites' HEAD loads while the BODY does not. Here is a snapshot of what happens on Science Daily from web console:

[00:30:26.362] GET http://www.sciencedaily.com/ [HTTP/1.1 200 OK 1412500ms]
[00:30:30.011] GET http://www.sciencedaily.com/styles/main9-new.css [undefined 1408859ms]
[00:30:30.021] GET http://www.sciencedaily.com/scripts/prototype.js [HTTP/1.1 200 OK 1408859ms]
[00:53:58.969] GET http://www.sciencedaily.com/scripts/functions9.js [HTTP/1.1 200 OK 1800047ms]
[01:23:59.030] missing } in compound statement @ http://www.sciencedaily.com/scripts/functions9.js:106
[01:23:59.542] GET http://images.sciencedaily.com/2012/03/120310150004.jpg [HTTP/1.0 304 Not Modified 110ms]

Please note the time gap there, it is exactly half an hour after which the body finally loaded.

What could be the problem? I cannot ping the website and traceroute ends somewhere in Amazon's cloud. So far I suspect misconfigured routing tables somewhere, how can I diagnose this and identify the responsible party?

Some important key information: Cannot ping or traceroute any of the affected servers. Sometimes the page loads forever without receiving any data. In some cases, I receive HEAD and the BODY loads exactly (1 sec precision) after 30 or 20 minutes.

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Tell us more about your network configuration and topology. I have seen this happen with an overloading router due to bittorrent traffic. –  G Koe Mar 12 '12 at 1:36
    
4 computers, 1xLAN, 3xWiFi, router D-Link DIR-600, no torrents. Doesn't matter though, because this happens all the time, on the same websites and even when only one computer is connected to the ISP's device which I don't have access to. –  JohnEye Mar 12 '12 at 1:45
    
@JohnEye You say your traceroute for this site ends in Amazon's cloud. Does the same apply to the other sites? i.e. are they all hosted by Amazon? Do other sites hosted by Amazon work? I'm just guessing here, but they might have blacklisted your IP. If you're on a dynamic IP, it might also be worth forcing a refresh. –  Bob Mar 12 '12 at 6:31
    
No, it's not only Amazon, other sites are hosted elsewhere. I have a static IP which my ISP refuses to change. Could there be some worldwide IP blacklists used by the approx. 1% of the Web I cannot access? –  JohnEye Mar 12 '12 at 15:14

1 Answer 1

The two most common causes of this that I run into are:

  1. Path MTU Dicovery black holes. Try manually adjusting your MTU on your client machine down to 1280 and see if those sites load. If they do, try higher numbers up to 1500 until you find the highest that works.

  2. Certain critical resources are on a server that is failing, down, or unreachable for some reason. Use your browser's ability to show you which files it's loading. If it allows you to cancel certain files that aren't loading, try that and see if the rest of the page loads in a usable fashion without the slow resource. One time this happened to me, it was because my machine was trying to connect over IPv6 to one server that was misconfugured and wasn't actually available over IPv6. Disabling IPv6 resolved that issue. Another time it was a failing ad network server, and enabling AdBlock got around it.

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1. Didn't help, even with MTU set to 1280 I cannot even ping the servers. 2. There is no way this could be the case, the websites work fine for everyone else, even for people who live nearby and have the same ISP. Proxies work as well. Also, IPv6 can be ruled out as one of the computers is running Win XP. Thank you anyway for your heroic effort, Incredible Spaceman Spiff ;-) –  JohnEye Mar 12 '12 at 4:20

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