Is Verizon FiOS blocking traffic from Windows?

I have a very interesting situation I am facing. I have Verizon FiOS as my ISP at home. I am trying to connect to a server inside my company's firewall. I VPN in, fire up Safari on my MacBookAir and type in the URL. I connect with the server - no issues. Next I boot up a VM running Windows 7 on the same MacBook. I fire up IE and type in the same URL. After waiting for a while, IE times out saying that the server did not respond in time. I try Firefox on the VM - same error. When I try Firefox on the host Mac OSX, I connect with no issues (just to verify its not a browser issue). Any other server inside the firewall, I can get to from the VM - not just this one. I even turned off the firewall on the Windows VM - no luck.

So, I think it is a VMWare issue and boot up my ThinkPad running Windows 7 natively. Same problem - I cannot connect to that server. I try it from Firefox, Chrome and IE. No luck.

I decide to take it one step further. I fire up the hotspot on my cell phone (coincidently also Verizon) and reconnect the VPN. Wonders - I can connect to the server. From all browsers on all three OS instances - Mac OS, Win 7 in a VM on the Mac and Win 7 native - no issues at all.

What do you think is going on here? Is Verizon FiOS or the router issued by them blocking (some) traffic from Windows 7 machines? Any ideas what may be the issue here and how can I fix it?