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The test first determines whether a user has access to any shared mailboxes. If shared access exists, the scan uses OWA to connect and measure connects and measures access latency. For users without shared mailboxes, the test is skipped.

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Autodiscover DNS Redirection

Challenges

All Outlook clients search for their configuration by performing a DNS lookup for Autodiscover.EmailDomainName.com.  In a properly configuration, this should be a redirection Outlook clients connect to the Microsoft cloud to retrieve configurations. To do so, a DNS lookup is initiated that, in a properly configured environment, should return the optimal path to M365's Autodiscover endpoint.   However, enterprises can often have intermediate redirections which result in variances in behavior on internal networks compared to external access.  

Approach - How it is done

TrueDEM performs a DNS lookup against Autodiscover.EmailDomainName.com and verify the returned domain name is tests if DNS lookups performed by the Outlook client return a domain name that is correctly directed to Microsoft 365's listed service.  (autodiscover-s.outlook.com)  

Value

AutoDiscover name resolution delays and name resolution loops can cause considerable confusion for internal IT teams.  Outlook desktop and mobile clients do not call out DNS resolution issues as the clients will eventually try M365 servers. This can result in clients that take many minutes to open a mailbox, look up other users, even send email with no clarity on why it is so slow.  

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