Forum Discussion
Mailbox access for external
Florian Maaß I would probably use a "Mail Contact" for creating an address in your tenant that was pointed to the External e-mail. You could also use Alias on existing accounts and then Rules to direct the messages where you wanted.
You can do both of these in the ECP or your tenant.
https://outlook.office365.com/ecp/?rfr=Admin_o365&exsvurl=1&mkt=en-US&Realm=contoso.com
Replace contoso.com with your own.
A Mail User account may also work but requires a little more preparation.
The only way the Send AS feature is going to work is to have a Shared Mailbox and give that person the correct permission.
A little trick I have learned to not have all the Shared Mailboxes show in the User Outlook Nav Tree is to use a group to assign that Send As permission on the Shared Mailbox. Even if that person sending the mail is the only one in the group. This way the Outlook client recognizes the permission but does not force it to appear in the user Outlook Nav Tree.
Forrest_H Thanks a lot for the answer. I will see what I can do with the provided information.
Edit: I just noticed that I cannot access the link you posted. It requires a login and my account doesn't seem to work here. Can you provide the information in that link any other way.
Florian Maaß did you replace the contoso.com with your tenant? The link I provided should take you directly to the Exchange Online administration portal.
Please copy the link to a text editor and then modify contoso.com to reflect your Office365 tenant and then you can copy and paste the updated URL into your browser address bar.
You can get to the same place via your Office 365 Admin Portal and then clicking Show More, and then Exchange