unable to connect to select domains

I'm kinda experiencing an odd problem. I'm unable to visit a particular domain.

Normally, when a website is down, you get some sort of error - an error 404, an unresolveable domain name error, or something. In this case, I get no error, what-so-ever.

I tried taking a using the Firefox plugin Live HTTP Headers to see the HTTP request my browser was sending (and to see what I was recieving), but... it didn't show anything. It didn't show an HTTP request let alone an HTTP response.

I tried accessing the website through an open proxy, and... it worked. So the problem is obviously not with the domain.

I wrote a PHP script to grab the contents of the domain, and... that worked, too. Here's the contents of the script:

$proxy = fsockopen("tcp:--domain.tld", 80, $errno, $errstr, 1);

fputs($proxy,"GET HTTP-1.0-r-n"); fputs($proxy,"Host: domain.tld-r-n-r-n");

while (!feof($proxy)) print fgets($proxy); fclose($proxy);

So the problem doesn't appear to involve my IP address, either. Rebooting didn't fix the problem, the problem manifests itself in both Firefox and Internet Explorer, and... all in all, I'm quite confussed (and annoyed).

Any ideas?