Welcome to the forums.
I look after the internetio.com site and demo panel and such, so I just had a quick look at it and it all seems Ok from here.
I then jumped onto the site using my Android phone running aPAC, and it works as it should.
Sadly (thankfully? I am not much of an Apple guy, so I will need to track down those that are here at Opto and see what happens when an iPAC device hits the site.
At a guess we need to make sure that you have not turned on any VPN settings on the iphone... the fact that its doing the same thing over the net as intranet is suspect in my mind.....
Also not sure if there are any NAT or such settings in the Airport Express that might be diverting the return packets.....
Lastly, drop firstname.lastname@example.org an email and see if those guys have come across this before.