[users@httpd] No response recieved from Apache at some external locations, but not others

["Robert Elliot" <Rob@xxxxxxxxxxxxxx>]

Hi, I'm having issues running Apache/2.0.59 (Win32) DAV/2 mod_auth_sspi/1.0.4 mod_ssl/2.0.59 OpenSSL/0.9.8c SVN/1.4.0 Server on Windows Server 2003.

I reckon about 60% of external people can see the website, and 40% cannot.  Unfortunately all three of my external attempts to retrieve a flat HTML file fail, from work, client site and my PDA's GPRS.  IE and Firefox both sit waiting for a response forever if I request a legitimate file.  If I request a nonsense one I get an accurate 404 from the server, examining the response in Fiddler reveals it is definitely an HTTP response served by my server, it shows my server's config.  What's more, Apache does seem to log my attempts that fail as 200 requests, and nothing appears in the error log.  So my request is getting through; but no response gets back to me.  nmap run from work also correctly identified my server as running Apache configured the way I have it, so nmap can get a response back. Just not, it would seem, any web browser when asked to serve a valid file.

 

Obviously it is not a firewall or DNS issue as lots of people can get to the site from outside using the domain name, I can get a 404 from the server, nmap can get a response and my requests get logged.

 

Any bright ideas?  I'm currently very confused.  It's either Apache, my router or my ISP losing or misdirecting the HTTP response, I presume... unless certain networks refuse HTTP responses from my ISP?  But my ISP swears blind that several companies run web servers using accounts with them, and the fact that the 404 response gets through suggests the communications channel is OK.