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Preventing duplicate SMTP addresses on Exchange

See our expert's advice for dealing with and removing duplicate SMTP addresses.

Can I delete the "created" SMTP addresses from the current list of external contacts in my GAL? I'd also like to know if I can set up a recipient policy to prevent SMTP addresses from being created for an external contact?

I'm unable to set up a normal user's email due to duplicate email addresses. In one case, I altered the SMTP of the external contact so I could use the appropriate address for my standard user account. The user's primary address is their real email address. There is no forwarding allowed on this Exchange server, so I'd like to know the implications of duplicate SMTP email addresses from external contacts.

If you created a secondary SMTP address you can remove it. However, you need to make sure no one is sending to that address before you do so or you risk losing mail. I am not aware of any way to block contacts in the GAL from getting an SMTP address through use of recipient policies.

SMTP addresses need to be unique within your Exchange organization, which is why you can't have the same SMTP address on a contact as on a mailbox.

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