I have been contacted over the last couple of weeks by some existing customers who claim they cannot connect to the website(s) I host on a Win2003 Webserver.
Whenever they call me I jump straight onto a machine in the office and check to make sure I can view the website. I am able to view them and navigate throughout the site(s) without a problem using an office broadband connection we have. At the same time I am browsing the site(s)they are telling me they cannot connect from there locations in the UK.
I also have a mobile broadband USB that uses a different ISP to the the office broadband, this also connects at the same time without any issues.
Does anyone have any experience in what to check on the server that may be causing a problem?
I don't think you have an IIS problem as such. On my Windows 2008 server I would look at Event Viewer | Windows Logs | System. Actually I would look At Events Viewer | Custom Views | Server Roles |Web Server - but that may have been set up specially on my server.
It could be, of course, that your customer has a problem with their internet connection.
I've seen this several times (customer can't access, but others can). Most of the time it's been a routing issue that affects the client's ability to get to the site (router down or misconfigured somewhere between client and site). I've even seen problems where someone just a few miles away from me couldn't get to the site while I could- simply because they were using a different ISP.
I've also seen issues where a customer's DNS was flakey and they could get to the site through the site's IP address but not through the domain name.
One other thought- check your server's/network's firewall. If your client has a dynamic IP, perhaps they had a new IP issued that fell into one of your blocked zones.