AirPort Extreme can't connect to RDP or Exchange

I have an update and it isn't good.
Thisproblem happens completely randomly. I can't connect to my company's email, RDP, or web server. When I remove the Airport Extreme and connect directly to the internet, or use my old router it works fine. Keep in mind I am not switching internet connections or external IP addresses - I checked. The IP address Comcast assigns me doesn't change no matter whar router I use. Everything else works fine. So my plan is to call Apple support when I have this problem. I have no idea when that will be - the last time was a week ago and it was too late to call.

Another update - even worse.

I just tried using Google's public DNS servers - nothing.

I called Apple and was forwarded to their senior techs who contacted their engineers. They want me to try it from another location. Easier said than done, but I still did it and the same thing happened.
I don't understand their reasoning. When I disconnect the Airport Extreme, and use my old router - a Buffalo everything is fine.

So I don't know where I go from here. If this is a flaw with the Airport Extreme, sending me a new one won't help because the new one would have the same problem.

It seems there are other people with the same issue, random sites aren't working on random days for no real reason. ore people need to call in before they acknowledge there's a problem.

Month later - no resolution. At this point I'm insisting on a refund.

This is obviously a problem with the Airport, not my ISP.

No, I was forced to return the router. After speaking to Apple's engineers nobody could figure out what was going on. We confirmed there was no problem on the server side and nothing was being triggered such as a security or firewall block.

That's not true.

I used a PC and it worked fine until all of the sudden it would simply quit for a period of 24 to 48 hours.

Made absolutly no sense.

I had no choice but to insist APple take the router back. I hated doing it, but that was the only solution. I started a new job and sometimes I had to connect at night. If I couldn't connect my job was in jeopardy.

This was the first major issue I have ever had with an Apple product. In my opinion this is a Microsoft issue and Misocoft intentionally makes things difficult for Apple products to work with their proprietary junk, such as RDP and Exchange. They makes things hard on Mac userstoforce them to switch back to PCs.

One thing you might want to do is ask your systems admin if the firewall is being triggered. Sometimes there can be a percieved attack and they start blocking your IP address. That was happening to a friend of mine who was using an Airport and trying to connect to his company's (Lockheed) VLAN. I'm not sure how they fixed it, but once he told his admin what was happeniend he did something to get it working again.

It was similar to what we experienced. Everything was fine, and then suddenly we're blocked for no apparent reason.

There was no way I would ask the company ID guy to open a port. I did discover something with my current Buffalo router, "pings" must be turned on. If I uncheck "block anonymous WAN requests (ping)" I can't get in. Once I turn it back on, it works fine. My prevous router was old and did not support uPNP.

I don't remember a similar setting on the AirPort.