We are seeing some weird behaviour on our exchange 2013 environment.

We have had Exchange up and running for over a year now with very little issue, currently on CU6. However in the last couple of weeks we have seen some issues with Autodiscover. It appears only to affect external users whose email address match their UPN, ie. Users who use an email alias of a different domain seem not to be affected.

User UPN - @companya.org.uk

Autodicover using @companya.org.uk fails

Autodiscover using @company.com works

There have been no changes to our autodiscover or DNS. After some extensive testing I have narrowed it down that only Outlook 2013 clients seem to be affected. So I brought up fiddler and noticed that when using the affected domain to try and autodiscover the request was then being routed to ActiveSync URL rather than the Outlook Anywhere URL. So further investigation of the Autodiscover logs it seems that users with the most recent Office client updates seem to be sending a different Useragent string than those without the November updates.

Pre November 2014 office update user agent string- Microsoft Office/15.0 (Windows NT 6.1; Microsoft Outlook 15.0.4667; Pro)

After November 2014 office update user agent string - Outlook/15.0 (15.0.4667.1000; MSI; x86)

I have proved there to be an issue as I uninstalled Outlook from my machine and reinstalled RTM with no updates and autodiscover works fine.

Is it possible that this changed user agent string is stopping exchange recognising that Outlook should use Outlook Anywhere? And even if that is the case why it only happens when using the UPN domain for autodiscover? Has anyone else seen this issue with the latest Office updates?

• Edited by scotta001 Thursday, November 27, 2014 1:04 PM Typo

Hi ,

1.Have you tested it via EXRCA .If so what would be the results for any one of the recipient in the problematic domain i.e (@companya.org.uk)

I should have mentioned all EXRCA test come back fine.

Hi,

When users whose email address match their UPN (User1@companya.org.uk) access Exchange 2013 from external internet environment, the Autodiscover service would try autodiscover.companya.org.uk instead of autodiscover.domain.com to connect to Exchange server based on the email address. For example:

1. Two predefined URL methods by using DNS:

HTTPS root domain query (https://companya.org.uk/Autodiscover/Autodiscover.xml)

HTTPS Autodiscover domain query (https://autodiscover.companya.org.uk/autodiscover/autodiscover.xml)

2. HTTP redirect method (http://autodiscover.companya.org.uk/Autodiscover/Autodiscover.xml).

3. If it fails, it would try SRV record lookup method.

Therefore, we can create a SRV record on companya.org.uk to forward Autodiscover requests to mail.company.com (or autodiscover.company.com) which is authenticated and pointed to Exchange 2013 for external accessing:

Service: _autodiscover

Protocol: _tcp

Port Number: 443

Host: mail.company.com

Additionally, I suspect there are two email address for your Exchange users with one is for your internal domain (companya.org.uk) and one for external domain (company.com). It is recommended to use User1@company.com for external access instead of User1@companya.org.uk because the autodiscover would refer to the SMTP email address to detect the domain for autodiscover service connection.

Regards,

All of that is in place, and as I say this has worked perfectly well for a year, it seems that only this issue occurs where users have the latest updates to office 2013 applied.

The issue for some of our customers is they don't have a domain of their own and so have to use the @companya.org.uk address, for these users there is no workaround.

All of that is in place, and as I say this has worked perfectly well for a year, it seems that only this issue occurs where users have the latest updates to office 2013 applied.

The issue for some of our customers is they don't have a domain of their own and so have to use the @companya.org.uk address, for these users there is no workaround.

Apologies, this was my reply, I was logged in under my personal account.

So after some further investigation it seems that KB2899504 is the culprit for us.

With the update on Autodiscover fails, uninstall it and it works.

Anyone else had issues with Autodiscover and this update?

In case anyone else is having this issue, after working with Microsoft they have confirmed KB2899504 & KB2986204 are the culprits behind this and that there should be a fix in place by the end of February.

• Marked as answer by scotta001 Monday, January 05, 2015 10:40 AM

In case anyone else is having this issue, after working with Microsoft they have confirmed KB2899504 & KB2986204 are the culprits behind this and that there should be a fix in place by the end of February.

Scott, have you been able to determine whether or not this issue has been fixed yet?  Microsoft released another update for Outlook 2013 in early February, KB2956087, could this be the fix you referenced above?

Well, it's March and two different updates for Outlook 2013 have been released: KB2956087 in February and KB2956170 just this week.  Neither of them seem to contain the fix for this issue.  Can anyone out there confirm this?