Get All Email Addresses used on Exchange Server

An administrator asked if it was possible to get a list of all email addresses in use on their Exchange server. Their Exchange server accepted mail for several domain names and they needed to know how many mailboxes they'd need if they moved one domain to Office 365.

If you need all addresses, including those assigned to mail-enabled public folders, you can use the get-recipient cmdlet. This cmdlet gets all of the address on the server where the user, contact, or public folder has an address within a specific domain.

get-recipient | where {$_.emailaddresses -match "slipstick.com"} | fl name,emailaddresses <> addresses.txt

When you need just the email addresses assigned to mailboxes, you can use a simpler cmdlet:

get-mailbox | fl name, emailaddresses <> c:\addresses.txt

To get just the addresses used by mail-enabled public folders, use the Get-MailPublicFolder cmdlet:
Get-MailPublicFolder | fl Name,EmailAddresses <> pf-addresses.txt

The cmdlets will output the addresses to a text file in the current directory (C:\Windows\system32, as seen in the screenshot), unless you use a fully qualified path in the filename, as we do in one example.

The output from any of the cmdlets will be in this format:

Name           : besadmin
EmailAddresses : {smtp:b@slpstck.invalid, SMTP:besadmin@slpstck.invalid}

Name           : Company Car
EmailAddresses : {smtp:CCar@slpstck.invalid, SMTP:car@slpstck.invalid}

Name           : Diane Poremsky
EmailAddresses : {smtp:DPoremsky@slpstck.invalid, smtp:DianeP@slpstck.invalid, SMTP:diane@slpstck.invalid}