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Tom Arbuthnot MVP
Tom Arbuthnot MCSM Communications

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Skype for Business Server 2015 CU7 Now Supports Blocking external NTLM (username/password auth) for Security

Published 02/10/2018 - 0 Comments

An open potential issue with SfB server has been the potential to get a list of accounts, try lots of random passwords and lock those accounts out.

With the new Get/Set-CsAuthConfig cmdlets in CU7, you can shut down NTLM and Forms Based Auth externally.

For more PowerShell information:

Then, you configure your servers to only accept Certificate Based Auth externally. (NOTE: You need Modern Authentication to use CBA.)

Now username/password auth is disabled, your users use Certificate Based Auth to get in externally

Here is an article that explains the details:

Original Microsoft post:

Tom Arbuthnot

Tom Arbuthnot

Principal Solutions Architect at Modality Systems
Tom Arbuthnot is Principal Solutions Architect at Unified Communications specialist Modality Systems. He is a Microsoft Certified Master and MVP, blogger, has a regular podcast with UCToday at and is a regular speaker at events including Microsoft TechEd and Ignite. He co-runs The Microsoft UC User Group London.

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