Web server not reachable from certain locations

Posted on 2009-02-09
Last Modified: 2012-05-06
I am running a web server that suddenly I cannot reach from certain locations  but is fine from others. The server at does not respond to browsers from my home office, but works from the office of my colleague. It does respond to pings from everywhere I have tried.
I works fine from my hosted server at Amazon web services.

Most intriguingly, I set up monitoring Their monitor located in Austria shows the site as up, but the ones in Germany and the US show it as down.

I am not aware of any firewall or VPN settings that have been changed lately. The server is Sin 2008/IIS7.
Question by:goldband
    LVL 38

    Expert Comment

    by:Hypercat (Deb)
    This sounds like a DNS issue, because it seems likely that some of these locations have cached information that is incorrect, while others have updated information that is correct - or vice versa.  Has anything changed recently in terms of host names, IP addresses, etc., for your site? If you host your own DNS server, then I'd check there for errors or problems with the server, changes that haven't been made properly or aren't replicating properly, any problems with the router/firewall (if any), etc.  If your DNS is hosted outside, then check with that service provider to see if perhaps they are having problems or something has changed on their end and is not replicated properly to all of their DNS servers.

    Author Comment

    I used the IP address directly with the same result. Consider the web server at, with IP address The page loads from Amazon web services and the Austria monitor of, but not my home network or the Germany or US monitors, even using the IP directly. Doesnt this take DNS out of the equation?
    LVL 22

    Accepted Solution

    Yes, that would rule out DNS if you are not able to access it by IP.
    This sounds like an IP address problem.
    Responding to a ping implies that the IP is live and usable, what it does not tell us is that you are pinging YOUR machine.
    If you can, do a tracert and see where the packets are going.  Somebody could have a bad IP address or rangle of addresses out there that is interfering with your server and site.

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