Autodiscover? – What? – Deep Dive Series Part 1

ehlo!

Everyone is talking about Autodisover in Exchange and since Exchange 2013 it is more important than ever. But did you really know how the process works?
I know – there are plenty of blog posts out in the internet but I thought I start the challenge from scratch and do it the complete way.

Let’s do some steps behind Autodiscover and what it is:
From an Outlook configuration perspective Autodiscover is just an XML file with some content – brought to you by your Exchange Servers. Outlook tries to find its configuration by using the Autodiscover-Service.

Outlook tries 5 ways to figure out where the Autodiscover XML File could be reached:

  • Service Connection Point in Active Directory (only for domain joined clients
  • SMTP-Domain: https://smtpdomain.tld/Autodiscover/Autodiscover.xml
  • Autodiscover HTTPS: https://autodiscover.smtpdomain.tld/Autodiscover/Autodiscover.xml
  • Autodiscover HTTP: https://autodiscover.smtpdomain.tld/Autodiscover/Autodiscover.xml
  • Autodiscover check for SRV lookup for _autodiscover._tcp.<smtpdomain>

Normally a domain joined client will always use the SCP. For this blog post we will figure out what the SCP is.

A Service Connection Point (SCP) is a property that can be found in the Configuration Partition within Active Directory. In it’s simplest definition it is a URL to your Exchange server. You configure this URL by setting the AutoDiscoverServiceInternalUri within the Set-ClientAccessServer (Exchange 2013) or Set-ClientAccessService  (Exchange 2016).

So with just one simple command you configure the SCP to reflect your Exchange Servers. After the default installation of Exchange the internal hostname will be listed there – for example: https://forpeex16-01.domain.local/Autodiscover/Autodiscover.xml

If you add another server a second SCP with https://forpeex16-02.domain.local/Autodiscover/Autodiscover.xml will be created.

Because of the namespace design in Exchange it is highly recommended to change this URL to something like https://autodiscover.domain.local/Autodiscover/Autodiscover.xml

Behind Autodiscover is your loadbalancer IP or if you do not have a loadbalancer the IP-Adresses of your CAS Servers (Exchange 2013) or Mailbox-Servers (Exchange 2016).

From an Outlook-Client perspective Outlook is configured to use the SCP on a domain joined machine. This is hardcoded in Outlook. OK – enough for today – I’ll have enough to say about Autodiscover the next time…

Your EXGuru – aka Peter Forster – aka Satschent Peter

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