CorvettePower.COM
28Oct/04

Running Exchange Outlook Web Access behind a Linksys Router

For some time I have run my Outlook Web Access from behind a Linksys Firewall Router with no problem. In the past, I had my default website running on one machine on port 80, and my Exchange server runing on port 6969 (since it was a different machine I needed a different port for it). My rules in the Linksys's forwarding settings looked something like:


Forward:

WEB     80:80 TCP -> 192.168.1.2
OWA 6969:6969 TCP -> 192.168.1.3



When I got around to installing an SSL certificate, I also found that I was running out of forwarding slots (Linksys allows around 10). So when I setup SSL, I also configured the Linksys differently, utilizing a newer feature called UPNP Forwards. On this page, they have known ports that you can enable and allow it to do the forwarding. So I left port 80 on the static page, and moved my 443 configuration to the UPNP page.


Forward:

WEB 80:80 TCP -> 192.168.1.2

UPNP Forward:

OWA 443:443 TCP -> 192.168.1.3


I set this up and everything worked perfect. I think also pointed a 'virtual' server on WEB to respond to mailserver.domain.com that did nothing but redirect incoming requests to https://mailserver.domain.com/ which allowed me to just type in mailserver.domain.com without having to remember the HTTPS, but always ensured i was doing HTTPS. When I first started having wierd issues, I thought maybe things were getting confused because for the same DNS name, i was talking to two different boxes in the backend. This really isn't an issue, but when things go crazy, you start to evaluate everything.


So everything works after I set this up. Then over the next month or two, I start seeing issues where I will have a OWA session open, and after a couple days of it just working, providing popup of new emails. It hangs, and when I click on it. The browser says it can't find the server. If I hit refresh, or close the browser, nothing changes. I can no longer bring up my OWA address. Other addresses on port 80 are working fine. If I goto another machine. OWA works fine! So I start to think maybe my client has problems, or the SSL cert expires, or I'm dropping packets. After much troubleshooting, on a whim I change things back to being all static Forwards. And I haven't had a problem since.


So if you use UPNP use it for something that doesn't persist a connection. I still am not sure what exactly the problem is, but I know I'm sticking with OWA in the static forwards table.

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