I am the tech support for a small business. Their internet access is through a local wireless ISP (business class). They have a static IP. A few months ago the office manager told me a web site she has to go to once a month (piee.eb.mil) suddenly became unreachable. No error message other than the web browser complaining it couldn't reach the site. It is NOT a DNS issue, it is not an Antivirus issue. You can do a trace route and you can see the packets just die after it gets to their ISP's upstream central hub. I contacted the wireless ISP and (of course) they say there is no problem on their end or their upstream provider. So I asked them to move us to another static IP. They did, and the site was reachable again. A couple of days later they check and it's back to being unreachable. This particular business has a branch in a different town about 5 miles away, and it's on the same tower of the wireless ISP, but a different static IP block. They can access the web site fine. I looked on the piee.eb.mil site to see if there was a technical contact I could email but was unable to find one.
So Firefox's latest browser has a built in "Free VPN", so I configured it today and I can access the web site just fine, from the same office. The only thing that is different is our IP address since it's going through Firefox's VPN. This provides my client with a work around, but I'd sure like to know what's going on and why the web site appears to be blacklisting my customer's IP address for no apparent reason. Any ideas? Or suggestions as to another subreddit that might be more appropriate for this question? Thanks.