Allow only specific external domains

Here is the clear answer to your question.

The setting “Allow only specific external domains” does NOT control how a participant appears inside a meeting. It only controls federation (chat, calling, and presence) between organizations.

Now, regarding your scenario:

If you configure:

– External Access = “Allow only specific external domains”
– Anonymous join = Disabled

Then a user from a non-allowed domain will NOT automatically join as Anonymous.

What happens depends entirely on authentication:

If the user joins while signed in with their work account, they will join as an authenticated external user (showing their real name and organization), as long as the meeting settings allow external authenticated users. The External Access restriction does not convert them to Anonymous.

If the user tries to join via browser without signing in, and Anonymous join is disabled, they will simply not be allowed to enter the meeting. They will not be converted to Anonymous — access will be blocked.

So to summarize:

– External Access restrictions do not affect meeting identity.
– Anonymous status depends only on whether the user is authenticated and whether anonymous join is enabled.
– If you disable anonymous join, unauthenticated users cannot enter.
– Authenticated external users can still join with their real identity, even if their domain is not on the External Access allowed list.

If your goal is to prevent Anonymous participants, disabling anonymous join is the correct control.