The Autodiscover Internal\External URL

I’ve learned a lot about Autodiscover recently, I’ve meddled with it for years but a recent project has taken me to new depths and I thought I’d offer one titbit of information that had me confused for a while.

The Autodiscover Internal and External URL’s as accessible via the Get-AutodiscoverVirtualDirectory cmdlet are not required in Exchange 2007 or 2010! They are a red herring in your quest to understanding how to publish Autodiscover correctly. In Exchange 2013 the Internal\External URL attributes have been deprecated from the AD Virtual directory which will save us all some confusion.

Access to Autodiscover is achieved internally using the Autodiscover URI which can be viewed using the Get-ClientAccessServer cmdlet and corresponds to the SCP records in AD that Outlook looks for if logged onto and talking to your domain.

Access to Autodiscover externally is nothing more than a DNS entry, Exchange doesn’t care per se how you reach it, its simply name resolution of autodiscover.yourdomain that leads the outlook client to your perimeter. Better description here

If you think about it why would an Autodiscover External or Internal URL be required, the entire purpose of the other CAS URL’s is as endpoints to the various Exchange services, if you are already fetching the Autodiscover.xml why would you need URL’s to talk to Autodiscover?



Bending an F5…

I was recently tasked with implementing an Exchange 2010 environment fronted by an F5 load balancer, sounds great right. One hitch the F5 was running version 10.2.0 and all over F5’s website and deployment guide they tell you that 10.2.1 is the minimum version for publishing Exchange 2010.

What does this really mean? From version 10 F5 have included Application Templates for various applications basically giving you a wizard for the otherwise very complicated configuration. In 10.2.0 the application template is missing a few vital components and contains a few errors, for various reasons the client I was working with couldn’t update so we had to try and make it work.


  • Follow the pdf to the letter, I highly recommend using the provided info sheets.
  • You can only run the template once for all your services, ie you can’t fill in Outlook anywhere and then go back and add ActiveSync (On a shared IP at least) so make sure you do them all at once.
  • Auto discover is missing from the template, you will need to manually create the pool and monitor as per the appendix tables on page 68.
  • Ensure you complete all the modifications to the template, page 22. Take note of the multiple monitor accounts.
  • Beware the I-Rule on page 75, this rule is the bread and butter of how the F5 separates the CAS services if you are balancing them on a shared address. The URL’s included eg  “/microsoft-server-activesync” are case sensitive and incorrect in the I-Rule provided. This took us 2 full days to solve. Make sure they match your Exchange URL’s exactly.

If this helps one person past the same situation I’ll be a happy man, a week trying to get this F5 working and no content on the web makes for frustrating times.