Sorry for the late reply. I got Mattermost working with ADFS, but ran out of time to document.
Here is the update:
The customer is using ADFS 3.0 and Windows Integrated Authentication (WIA) is enabled as shown in the picture. This is a global setting.
From powershell on the Windows server, the Mozilla/5.0 user agent was added to the WIASupportedUserAgents for other apps. The Mattermost app uses Mozilla/5.0 in its user agent, so Windows Integrated Authentication is used by ADFS. It looks like the Mattermost app supports Forms-based authentication, but not Windows Integrated authentication.
The following command was set in my environment to enable the Mozilla/5.0 user agent as well as a long list of other user agents to support WIA.
Set-AdfsProperties -WIASupportedUserAgents @(“MSAuthHost/1.0/In-Domain”, “Mozilla/5.0”, “Firefox/55.0”, “MSIE 6.0”, “MSIE 7.0; Windows NT”, “MSIE 8.0”, “MSIE 9.0”, “MSIE 10.0; Windows NT 6”, “Windows NT 6.3; Trident/7.0”, “Windows NT 6.3; Win64; x64; Trident/7.0”, “Windows NT 6.3; WOW64; Trident/7.0”, “Windows NT 6.2; Trident/7.0”, “Windows NT 6.2; Win64; x64; Trident/7.0”, “Windows NT 6.2; WOW64; Trident/7.0”, “Windows NT 6.1; Trident/7.0”, “Windows NT 6.1; Win64; x64; Trident/7.0”, “Windows NT 6.1; WOW64; Trident/7.0”, “MSIPC”, “Windows Rights Management Client”)
For a test, I removed Mozilla/5.0 from the WIA Supported User Agents LIst.
Set-AdfsProperties -WIASupportedUserAgents @(“MSAuthHost/1.0/In-Domain”, “Firefox/55.0”, “MSIE 6.0”, “MSIE 7.0; Windows NT”, “MSIE 8.0”, “MSIE 9.0”, “MSIE 10.0; Windows NT 6”, “Windows NT 6.3; Trident/7.0”, “Windows NT 6.3; Win64; x64; Trident/7.0”, “Windows NT 6.3; WOW64; Trident/7.0”, “Windows NT 6.2; Trident/7.0”, “Windows NT 6.2; Win64; x64; Trident/7.0”, “Windows NT 6.2; WOW64; Trident/7.0”, “Windows NT 6.1; Trident/7.0”, “Windows NT 6.1; Win64; x64; Trident/7.0”, “Windows NT 6.1; WOW64; Trident/7.0”, “MSIPC”, “Windows Rights Management Client”)
After that, when clicking login via SAML, I’m presented with an ADFS login screen and everything works.
However, in the real environment, the Mozilla/5.0 user agent can not be removed.
Is there a way to get the Mattermost app to work with WIA?
