Inquiry about the issue where both the subdomain and top-level domain are displayed in the recipient address.

Question

Hello,

I have a question regarding a situation where multiple SMTP recipient addresses are being displayed. In an Exchange hybrid environment, there is a user with a subdomain-assigned Secondary SMTP of sub.test.com, and a Primary SMTP assigned as test.com.

When this user sends a message to an internal user, the recipient sees both the subdomain, sub.test.com, and the top-level domain, test.com, in the reply address.

Is this an intended behavior?

Thank you for your assistance.

Answer 1

Hi @ 정석원_MS,

Based on testing, I found that this is the email addresses shown in the username slice, not the reply box.

In my test environment, the subdomain address of the mailbox was also displayed as well as the primary address, so this is expected behavior for this scenario.

Hope this helps!

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Answer 2

Hi @ 정석원_MS,

Sorry for the late reply.

According to my research, this display is by design. If you don't want to receive emails from your root domain email address, I recommend that you could delete it and keep only the subdomain email address.

Or create a mailbox rule in the root domain mailbox to redirect all messages to the child domain mailbox.

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