Why using MAPIBlockOutlookExternalConnectivity is a bad idea

A while ago we had a special request: For a dedicated AD site, only a subset of users should be able to access their mailbox with Outlook for Windows from outside the corporate network. My first thoughts were this is not possible. I wasn’t aware of any setting to limit Outlook Anywhere or MapiHttp external access on user base.

But we were told by a PFE that there is a way:

Combining MAPI over HTTP configurations and internal or external connections

There is always something new, you can learn!

We did some testing and the results were very promising. So we were able to fulfill the request.

But the description of Set-CASMailbox for the parameter MAPIBlockOutlookExternalConnectivity and the article doesn’t reflect all consequences and soon we received a lot of complains, reports about connectivity issues with devices and applications other than Outlook for Windows.

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Outlook, Lync/SfB, Cloud Based Discovery and prompt for credentials

It’s been a while since I was troubleshooting prompt for credentials. The last time I was happy to find the root cause and how to fix this (you can read about it here).

Now the same issue seems to come back. But this time it has nothing to do with proxy settings. This time it has to do with KB3114351 and KB3114372 from December 8, 2015.

There were besides security related updates also some major design changes implemented as described more in depth in KB3135145:

  • Cloud Based Discovery
  • UPN Enforcement for OrgID
  • SIP Autodetection from Azure

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Lync/SfB and Exchange:EWS not fully initialized

There are many reasons why you see this error. But last week I learned something new. I had a client, which showed this error in the Configuration Information and also this pop-up



At the same time the MAPI Information was shown with MAPI Status OK. As long as Outlook was running the user had all features, because the client was using the Outlook integration via UcMapi.exe.

First I checked the client for the correct internal and external EWS URLs and that those could be reached succesful.

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Outlook, Lync/SfB prompt for credentials?

In the last few weeks I had some complaints from users about Outlook, Lync/SfB prompting for credentials, after switching between networks (wired to wireless and vice vers). Users got pop-ups like this:


But not all of them and affected users even didn’t get them all the time.

This was going to be fun….

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Exchange and Lync Room System (LRS): Are you in a supported scenario?

Over the last few month the popularity of those devices dramatically increased. Lync Room System (LRS) are changing the culture of meetings and bring them to another level. Personally I think those devices are pretty cool and useful, only the prices could be a shocker. But as time goes by even those prices will drop. In this post I will not cover how to setup those systems. I want to point your view at supportability of those devices in enterprise environments. I’m now looking at LRS only from Exchange perspective and about what I’m struggling. Continue reading