You requested it... and we delivered it in Exchange 2010!
One of the most requested items in exchange 2007 was something like this...
...we have 5-12 external domains that we need to allow some users to send to, but prevent sending to all other domains...
Or like this...
...we need a way to allow everyone to send to the internet but restrict members of 'contract workers group' to just certain domains.
This blog post is meant to show how easy it now is to accomplish this oft heard request in Exchange 2010. Transport rules, introduced with Exchange 2007, provided a lot of new options for administration of mail resulting in even more requests for additional functionality. The rules now have new predicates and actions extending the possibilities of what can be done.
In particular, the predicates for address matching that were previously only available on the Edge role are now available for Hub role as well!
For more information about the new predicate and actions see the following links below:
Exchange 2010 Transport Rule Predicates:
Exchange 2010 Transport Rule Actions:
So I will use the 2nd "request" above to demonstrate how to create a rule in 2010 to accomplish it.
For our example, the rule will restrict "Active Directory Mail enabled users" who have their 'Department' defined as 'Temp Employees' from sending mail to the internet, except they must be allowed to send to 2 external domains called: 'partnerdomain.com' and 'fourthcoffee.com'. Additionally, to reduce Helpdesk calls, you want to send an NDR when they violate the rule. For demonstration purposes I will use 2 Conditions, one Action and one Exception.
--> the rest in on the blog :