Powershell script to remove smtp addresses with a domain from mailboxes in Exchange 2010

This script is to remove a smtp domain from a client’s mailboxes. Email address policy is how these domains get added to the mailboxes. However email address policies are additive only and cannot be used to remove the domain that was added using email address policy. They have to removed manually from each mailbox.

When will we need this?

A good scenario is when a client company ABC has changed their company smtp domain from abc.com to xyz.com and no longer want to receive any email on the old smtp abc.com that is they want that if somebody sends an email to abc.com they should get a bounceback. The old domain abc.com has been  removed from the accepted domains and the MX records for abc.com no longer point to your exchange server. Externally this will work correctly because obviously the DNS has been modified and abc.com has been removed from accepted domains in our exchange. But internally on the same exchange server, users will still be able to send and receive an email to abc.com address. The email addresses with abc.com either needs to be removed manually from each users exchange properties or you can use powershell to do it for you.

How will this work?

1       I am using a custom attribute for filtering the get-mailbox command, but you can use –scope to use OU for filtering or select all the users. Modify the customattribute1 value to the of the client and domain name (domain.com) to the target smtp domain in the script and copy the script

2       Open the exchange management shell and paste the script in the shell window (press enter once)

All the email address for client with clientcode ‘clientcode’ that contain email addresses with smtp domain ‘domain.com’ will be removed.

#Script to remove email address for a particular domain as EAP is additive Only

# BEFORE USING - please change the domain name and custom attribute as mentioned in comments

# IMPORTANT: DOMAIN IS NOT YOUR AD DOMAIN BUT THE SMTP DOMAIN YOU WANT TO REMOVE

#Gets the client mailboxes for the users with customattribute1 set as 'abc'

foreach($Clientmailbox in Get-mailbox -ResultSize Unlimited | where{$_.CustomAttribute1 -eq 'abc'})

{

#for each mailbox grabs the email addresses and filters the addresslist

#for the smtp domain the needs to be removed

#and then removes the email address

#CHANGE THE DOMAIN from domain.com to the corresponding domain

$Clientmailbox.EmailAddresses |

　　　 ?{$_.AddressString -like '*@domain.com'} | %{

　　　　　 Set-Mailbox $clientmailbox -EmailAddresses @{remove=$_}

　　　 }

}