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Complications With Setting Custom Port for OWA, Exchange 2007
Category: Tech
Posted by Jonathan Corbett on July 15th, 2009
With the number of IP addresses on the Internet currently fixed at about 4 billion, the goal of IP address conservation to make that number last has been around for almost 10 years now. As such, the common practice is to run multiple applications on 1 IP address, which can be done by using different ports. You can also run multiple HTTP Web sites on the same port, and indeed this solution works well.
...just don't do it with Outlook Web Access for Exchange 2007.
Here's just two of the reasons you'll likely encounter if you try:
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Port Address Translation, the art of taking incoming traffic on a public IP address and a certain port number and then forwarding it to a private IP address with a potentially different port number, isn't allowed for by OWA 2007. When configuring OWA 2007, you must tell it the hostname that you plan on using to access your webmail, and that hostname is used to build URLs inside of the Web application. That is, some links within OWA are coded to use an "absolute" URL based on the hostname provided, rather than a relative URL.
The problem is that Exchange will allow you to give it a hostname followed by a port number ("mail.yourname.com:12345"), but in practice, Exchange secretly strips your port number and replaces it with the local port that your request came in on. So, if your external URL is https://mail.yourname.com:12345/owa/ and you set port 12345 of your external IP address to forward to 10.1.2.3:6789, your first request will get to 10.1.2.3:6789 successfully, but as you continue to use OWA, you'll secretly end up at https://mail.yourname.com:6789/owa/, departing from your intended external port of 12345.
- Windows Mobile phones and iPhones have a built-in e-mail client that supports Exchange, but for all versions we could try at the time of writing, finding OWA on any port other than 443 (or 80, if you're brave enough to go cleartext, which later versions will allow) is unsupported. Similar to above, you're allowed to type in a port number after the URL, but it is stripped and always replaced with 443. So, if you want your Touch Pro, iPhone 3G, and likely countless other devices to function with your server using the built-in client, keep OWA at 443.
Happy 4th!
Category: Everything Else
Posted by Jonathan Corbett on July 4th, 2009
Wishing you and your family a happy and safe 4th of July celebration!
Blog Launch
Category: Company News
Posted by Andre Chambers on July 1st, 2009
We're starting the second half of 2009 with a new addition to our Web site: a blog. While it seems cliché to have a blog now that Web 2.0 has dictated everyone and their mother must have a blog, we think it will be a useful way for us to update our clients as to what's going on with the company as well as share some of the cool technology insight that we get on a daily basis.
Blog Posts by Month
- April 2010 (1)
- March 2010 (1)
- December 2009 (1)
- October 2009 (3)
- September 2009 (2)
- August 2009 (1)
- July 2009 (3)
Disclaimer: Blog posts are opinion and do not represent service offerings nor technical certainties, and FourTen will not be liable for their accuracy.