One of the things I remember when working with Small Business was dealing with a Smart-Host.

A Smart host, which most of us take for granted is the “SMTP” server most users get from their ISP.   When working with Small Business Server 2003 and most Small businesses, we didn’t tend to host our own mail internally.  It just wasn’t cost effective.   So we would choose an external vendor and use the POP3 connector from SBS 2003.

Now the problem.

If you are sending email and you are NOT hosting it yourself ON that server, you must send the mail to a REAL SMTP server on the outside world.  That’s easy.  Use the Smart Host from your ISP and life is good.

Ahhh but the catch.  Most ISP’s have restrictions and rules on how much you can send to those connectors.

Home users don’t notice it.  They do a send/receive and in the back end it just works, or they hit “Send Receive” again.


In a Server, it all has to just work.  No interruption, all magic, seamless.


So one of the Features I used to tweak under the Exchange 2003 allowed me to limit how much mail was sent out in each session.   I could throttle it down so the Smart Host on the outside world COULDN’T be spammed inadvertently, but at the same time Exchange 2003 could happily do it’s job.

Then Exchange 2007 came along.   It works beautifully, except for one thing.   I couldn’t find that setting!  I have a friend who does a lot of work for Small Business and HE couldn’t find it.   And he really needed to regulate that flow of mail!


Well as luck would have it, Microsoft did NOT remove the feature.  They reallocated it to the Transport Server role.   Which is actually better since instead of a single SMTP connector holding the setting a particular SERVER holds it.  That means if mail is flowing out of a particular Transport server on Exchange that has lower bandwidth, or restrictions than it’s partners; You can adjust it.


Set-TransportServer –identity ‘EXCHANGETRANSPORTSERVERNAME’ -MaxPerDomainOutboundConnections 5


The Default setting is 20 connections at a time.  Which is fine.   But Some ISP’s don’t want 20 live connections to their SMTP server from the SAME IP address at once.    And may either REJECT or BLACKLIST your server until you get all nice with Tech Support on the phone.

This article from Microsoft is a great starting point on learning how to regulate some of the mail flow in Exchange 2007.  For the most part it’s all done with Powershell 🙂


The Energized Tech