Exchange 2003 – Restrict sender from sending internet email
Posted on 10 July 2009
For whatever reason you may want to restrict a user from sending email to external users or even certain distribution lists within your Exchange environment. There are numerous ways to do this, and there are plenty of resources on the web. Some don’t mention the critical step of adding a registry key that tells Exchange to look for these restrictions. Without this key it won’t work. I am using a distribution list to identify the users I don’t want sending email email outside my organization.
- In Active Directory create a distribution list for example: no external email
- Add whatever users you want to this group.
- In Exchange System Manager navigate to your Internet Mail SMTP connector (mine was in Administrative Groups > First Administrative Group > Routing Groups > Connectors>)
- Go to properties on the Internet Mail SMTP connector > Delivery Restrictions tab > Reject Messages from: section.
- Add the no external email group you created in step 1
- On the Exchange Server create the following registry key: HKEY_Local_Machine\SYSTEM\CurrentControlSet\Services\RESvc\Parameters Add or Edit REG_DWORD Key called CheckConnectorRestrictions and set to 1
- Restart the Microsoft Exchange Routing Engine service and Simple Mail Transfer Protocol Service in service manager.
- You can also restrict these users from sending to various internal distribution lists by adding them to the distribution list properties > exchange general tab – accept messages from everyone except and add the distribution list in step 1. It’s also a good idea to check the “authenticated users” check box so your internal lists don’t get pegged from the outside.
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