No we do not use ISA!
We have a fortigate firewall/content filtering box, which you set policies on to, I have allowed HTTPS, HTTP, PING to the DMZ. I have setup NAT so that the external ip address NAT's through to the IP address in the DMZ.
There is no 404 error etc. it just says in the browser that page can not be found, check your internet connection, the website maybe experiencing problems.
Do I need to make changes in IIS, but I thought that was the alternative mapping did in MOSS 2007. I have not put a certificate on the site yet but this should not stop the page being seen.
I have have OWA setup and that works fine, so the policies etc on the firewall are working
Scott Slocombe