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Exchange Server Compatibility Information Exchange Server Version Compatibility 5.5* No 2000 Yes 2003 Yes 2007 Yes * May Adapt (More Information)

Groups - Secure Your Distribution Groups
Author: Simon Butler, Exchange MVP, MCSE

Working with Distribution Groups Home Page

Why Secure Your Groups?

Your distribution lists can be abused and should be secured. Spammers like to find the addresses of a wide distribution group as it makes their life much easier.

In many companies, there will be a group equivalent to "All Users". This group needs to be secured, but can also provide security for other groups that you may have. 

By securing the group so that only members of "All Users" can send to a message to the group stops anyone from outside from using the same list. This could be a spammer or a disgruntled ex-employee or even a current employee wanting to cause problems by sending a message in from a Hotmail account.

By using a group to secure the list means that when a staff member leaves, all you need to do is remove their group membership, without having to worry about other permissions.

Secure the Group - Exchange 2003

1. ADUC on the Exchange Server, right click on the group and choose Properties.
2. Click on the tab "Exchange General"
3. Adjust "Accept Messages" to "Only From:" and select the required list. For aditional security you can also set the "From authenticated users only" option as well.

Secure the Group - Exchange 2007

1. Open the Exchange Management Console and find the group you wish to secure. Right click on it and choose Properties.
2. Click on the tab "Mail Flow Settings" then select Message Delivery Restrictions and choose Properties.
3. You can then secure the settings as with Exchange 2003 by selecting a group and requiring the sender be authenticated. However in addition you can also set who messages are rejected from, which is different to Exchange 2003 where it was either accept list OR reject list.