Wow. First off skip to the end of my rant if you want to know how mine was fixed, like everyone else, I'm so glad I found this forum before I went one step too far telling off my ISP & Server Host. All along it was Apple that I should have saved my wrath for.
That being said, I was stuck in the same quagmire as everyone else. I'm a Web Designer and was testing a site so I was accessing the server repeatedly within a short amount of time. Then ka-boom, couldn't access the server through FTP or HTTP with my AEBS. After exhausting conversations with my ISP & Server host, I did what I should have done in with square one, google the problem, which brought me to this forum & misery loves company.
So I took my AEBS into the Genius Bar, it was out of warranty but worth a shot, so I told the guy about the problem and we hooked it up and...it worked. Of course, the Genius of course was more than happy to send me on my way. But low and behold, I get back home...the problem is still there.
This brings me to the fix this morning:
I was able to access the blocked server through my AEBS via an ethernet cable, so it's just wireless that seems to replicate the problem. I was testing the server with a few changes, then I was uploading a few files and left my computer plugged into the AEBS and connected to the FTP server. I was gone for about a half hour, when I came back. I unplugged the computer from the AEBS and connected via wireless.
Holy Crap, it worked. I emptied my cache, restarted my computer everything I could think of to make sure this wasn't a false positive. But, son of a gun...it's been able to access the site all day, no problem.
So, there ya go...I have no idea if it will work for anyone else, but it worked for me and it sure is nice to be wireless accessing a needed site again.
-p