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Suppose many companies are using Exchange 2010 for email hosting, and each company has a different TLD / Domain. The email hoster does not want to add Subject Alternative Names and opts for the SRV configuration of Autodiscover.

How important is it that they correctly configure the SRV record with the name _autodiscover.clientPrimarySMTP.com and have it point to serversubjectname.hoster.com?

What would break if the SRV is missing or misconfigured?

I suspect that 2007 and newer clients who are having issues with Out of Office rules is likely related to this.

makerofthings7
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  • Can you go into more detail about your out of office issues? Autodiscover should not be causing issues with that. It may be another issue entirely. – Tatas Feb 13 '12 at 17:15
  • @Tatas - see the accepted answer below... that is based on a conversation with MSFT – makerofthings7 Feb 13 '12 at 17:17
  • I'm not sure how that is the accepted answer? It doesn't go into what your issue with Out Of Office was. It also is a bit wrong, as public folders are not necessary in a pure Exchange 2010 environment. OOO, OAB, and Free Busy are not shared via public folders in EX 2010, they are web servies, as you can see by the output you pasted below. – Tatas Feb 13 '12 at 17:21
  • @Tatas - You're right, I updated the answer with correct information. I posted that several months in a hurry and never came back to it. Do review it and let me know what you think... – makerofthings7 Feb 13 '12 at 17:36

3 Answers3

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Autodiscover will configure the following services within outlook:

  • Out Of Office
  • Outlook Address Book
  • Unified Messaging
  • Availability Service (Free Busy)
  • Exchange Control Panel

The issue was reproduced with the following settings:

Configuration

School1 has a domain name of school1.edu. They host email at hoster1.com. School1 uses the "srv" method of locating the autodiscover record for autodiscover.hoster1.com.

What was broken

There are 200 different schools who are using the above mentioned configuration. We discovered a trend with customers having errors with OOO, OAB, and FreeBusy. This occurred for Outlook 2007 SP2 and newer clients who were previously on Exchange 2003, and migrated to 2010. All the profiles were set up manually.

Outlook 2003 was unaffected, since it uses Public Folders.

How we fixed it

The guidance was for the helpdesk to check the SRV record and correct it as necessary. In a majority of the cases, the SRV record was invalid or missing. The trick was to ensure that both external and internal DNS was updated with the correct SRV record (in the event school1.edu also had an internal DNS)

Lastly, due to how outlook first checks for an A record at autodiscover.school1.com, some DNS servers returned the results of a wildcard entry. Removing the wildcard fixed the issue. For people who want to keep the wildcard DNS entry, they may want to try creating the autodiscover.school1.com record as a CNAME or an A instead of an SRV (though I haven't tested it)

Sample Autodiscover image

makerofthings7
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If an autodiscover record doesn't exist, then clients will need to manually configure their Outlook and mobile devices. If it's incorrectly configured then you run the chance of clients getting the wrong settings applied to their Outlook or Mobile devices which can cause all sorts of issues.

Tatas
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  • Agreed. Not having a properly configured Autodiscover is definitely an inconvenience for end users, but it's in no way critical for Exchange operation. – Massimo Feb 11 '12 at 17:24
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    Agreed, it is not critical. But if configured correctly it can save a lot of time and issues with client setup. – Tatas Feb 13 '12 at 17:14
  • @massimo and tatas In my instance, all profiles were set up manually, then the MBX migrated to 2010. Somehow this made autodiscover required for a large portion of our clients running OL2007SP2 and newer. Not all were affected, but many were. – makerofthings7 Feb 13 '12 at 17:59
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To answer your direct question: Nothing would break if you don't configure SRV record on public domain. In fact, I don't even do it because even though the docs claim Outlook 2007 supports this, in my experience it plain doesn't. Only Outlook 2010 does. It's just Yet another strategy to get users to pay for the latest product.

What I do, is this:

  • Does telnet to domain.com port 443 connect or not?

If yes: {

If yes: You should now either disable port 443 on your public web server, or change the A record for "domain.com" to your Exchange box public IP.

If no: You should now ensure the same certificate is used on your IIS box and covers autodiscover.domain.com without error.

}

Now:

  1. Add an A record for "autodiscover.domain.com" to your Exchange box public IP.

  2. Obtain and install an SSL certifcate for CN=autodiscover.domain.com. This could be a free SSL certificate as we only require one host name to be secured here. If you want to be fancy and allow for "mail.contoso.com" to work, then be prepared to pay £60/year to GoDaddy for a UC/SAN SSL certificate.

  3. Ensure https://autodiscover.domain.com/autodiscover/autodiscover.xml shows some xml after logging in, and pressing F5 shows a new time stamp each time you refresh the page. Ensure http://autodiscover.domain.com/owa loads as https. Both should have no certificate warnings.

  4. Check the URLs for autodiscover using these Exchange Shall commandlets:- Get-OABVirtualDirectory Get-ClientAccessServer Get-WebServicesVirtualDirectory Get-PowerShellVirtualDirectory Get-ECPVirtualDirectory Get-OWAVirtualDirectory Get-ActiveSyncVirtualDirectory Get-AutodiscoverVirtualDirectory

servermanfail
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