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Discover the mailbox connection details in Outlook

Here’s how to discover what type of connection Outlook for Windows is making to each mailbox. That’s occasionally important information but it’s hidden in an unexpected place.

Connection Status has vital details to know if support asks what type of mailbox connection Outlook is using.  At the moment, Microsoft is shutting down access to older ‘Basic’ authentication so it’s important to know what type of connection Outlook is using.

Outlook Connection Status is available in all Outlook for Windows from Outlook 2007 onwards. Later versions have more columns of info, but the basics and how to access the Status box haven’t changed.

Can’t find the Outlook Connection Status? You’re not alone, see Opening the Outlook Connection Status box

Here’s a typical Outlook Connection Status dialog for two mailboxes: Outlook.com and Gmail (free).

Connection Status in Outlook 365 for Windows – Outlook.com and Gmail accounts.

Connection Status dialog is quite technical and hasn’t been updated for many years. The columns can’t be moved around and aren’t sortable.

Incomplete documentation

Microsoft’s documentation for Connection Status is woefully incomplete and out-of-date

Description of the Connection Status dialog in Outlook” was supposedly updated in July 2022 but doesn’t look it.  There are vital but missing details about modern connections to Microsoft’s own hosted systems. We’re talking about details that have been in place for some years yet still not made it to the documentation.

We had to dig around other sources to fill in some gaps.

That’s an astonishing lapse by Microsoft since there’s so much talk and trouble about the closure of the older Basic Authentication connections.

Missing data

The Gmail connection is IMAP (the default these days) but there’s no information about the security (or not) of the login.  Nothing in the Protocol, Authn or Encrypt columns. 

There’s no good reason for that beyond Microsoft’s self-interested focus on their own technologies.

(Paid Gmail accounts can use Microsoft’s Activesync system (same as Exchange Server/Outlook.com) but free Gmail mailboxes are limited to POP or IMAP connections. )

For the connections that Microsoft is willing to reveal, there are three columns of interest (for Outlook 2013 and later) regarding the security of the connection.

Protocol

Most likely HTTP or RPC/HTTP.

In olden days, mailbox connections used different protocols and port numbers. That caused a lot of trouble because firewalls would block access. So Microsoft switched to using the web page ports 80/443 which should never be blocked. The protocol is called RPC over HTTP or RPC/HTTP.

Don’t worry that it says HTTP, not HTTPS – the security is covered in the Encrypt column.

Authn

The method of authentication used. Meaning how Outlook passes your credentials to the mailbox.

  • CLEAR  or Clear*- (meaning Basic Authentication which is being turned OFF for Microsoft hosted mailboxes and needs updating)
  • NTLM
    • For older Exchange Server connections we’ve seen CLEAR (NTLM)
  • NEGO
  • KERBEROS
  • ANONYMOUS
  • AUTOLOGON

Not documented by Microsoft properly but used with Microsoft hosted mailboxes are:

  • MSA* meaning MicroSoft Account login
  • Bearer* denotes Modern Authentication

Encrypt

Possible values are:

  • ERROR
  • NONE
  • SSL
  • NO
  • YES

Ideally, it’ll show SSL or SSL (Yes)

Opening the Outlook Connection Status box

Office 2019 and Office 2016 losing important connections in 2023

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