Our OWA stopped working from the external IP. Not exactly sure when it stopped, so its hard to pinpoint what caused it. Updates from microsoft were installed recently. It works great internally. When hitting from an external IP, it does not make it to the login screen, just says page cannot be displayed.
My first thought was that the port was blocked on the firewall, but that has been tested and is open. I have ports 80 and 443 open. My default site refreshes and sends you to the exchange dir. I can see the default site load and refresh, so I know I'm hitting the server on port 80 at least.
I've read tons of articles, but not really found any that match exactly. There's a link out there for a problem with an exchange 2007 rollup that seem similar, but the problem ultimately was different.
This is on Microsoft windows server 2003 (sp2?) with exchange 2003 (ver 6.5.7638.1)