Include/Exclude settings help you to define whether email address with a particular domain should be automatically added or not added to newly created mailboxes, distribution lists, and public folders.
Note: These settings are not available for the default domain.
You can exclude the domain when adding the new domain to CONTROL PANEL. To exclude the domain select the check box and click Add button.
You can set the Include/Exclude option for a domain through CONTROL PANEL:
1. Navigate to Services > Domains
2. Click the domain name you would like to modify and go to the Include/Exclude tab. Change the settings accordingly.
You can choose between 2 modes: Included or Excluded.
If you choose Included mode, then every time you create a new mailbox, distribution list or a public folder, a corresponding email address with this domain will be automatically assigned to created mailbox,
You can also add a necessary domain to all existing mailboxes, distribution lists, and public folders at once.
To do this, simply check the box Create additional email addresses with this domain name for all existing mailboxes and public folders and click Save Changes.
If you choose Excluded mode this domain will bot be added to new mailboxes as an alias automatically. You will be able to add the alias with this domain manually. Read our knowledge base article What Are Email Aliases For An Exchange Mailbox?
If you need to delete all aliases with this domain from all mailboxes, distribution lists, and public folders at once, then check the box Delete additional email addresses with this domain name for all existing mailboxes and public folders and click Save Changes.