A good friend of mine and the Owner of Around the Clock I.T. Solutions Inc., Rick Lund-Pedersen had a bit of a stumbler.   A throttling feature that existed in Exchange 2003 and DOES exist in Exchange 2010 (which a Powershell Commandlet to Boot!) was MISSING from Exchange 2007.

We called it “maxmessagesperconnection” .

It allows us ITPros to limit the amount of messages sent out in EACH connection to a destination SMTP server.   In the case of those who use a SmartHost you’ll find some of them actually limit the number of messages you can tranmit in a single connection to reject possible spam flow.

Which is where this feature (which used to sit on the Virtual SMTP Server settings in Exchange 2003) was so badly needed in SBS 2008 and other sites using a Single Exchange 2007 server setup.  Such environments have a 100% locked off firewall and send all outbound mail to a Smarthost and use a FAST but inexpensive High Speed internet.  This completely negates the need for expensive onsite hosting while still leveraging all the power that Exchange 2007 has to offer.

But alas.  Microsoft (or Somebody on the Exchange Team to be more correct) in the ten Billion lines of code, misplaced a feature. 

MaxMessagesPerConnection.  But now that error has been corrected.  Download and update your Exchange 2007 Server to Service Pack 2 and some new objects will be in the Schema This service pack is ALSO approved for SBS 2008.  When you go to run it, it will have you download a VERY specific update for SBS 2008 (it’s small) that will launch and integrate Service Pack 2 for Exchange 2007 PROPERLY for Small Business Server 2008.  Once done, some new schema changes and features are added to Exchange 2007.

Amongst them, MaxMessagesPerConnection.  Now it’s not in the GUI or Powershell until Exchange 2010 but it IS there to edit.  Which is all we want.  Fire up ADSI Editor (Free download or if you’re using Server 2008 it’s already a part of your Management tools)

**** At this point, if you are NOT comfortable with editing Active Directory, stop.  This truly gets ‘Under the Hood’ and an “accidental Delete” will mean a restore from Backup. ***  TAKE WARNING AND TAKE HEED AND DO NOT EDIT THIS LIGHTLY ****

Once in ADSI Edit you’ll need to change “Select a well known naming Convention” to Configuration once the console loads up.


Once in you’ll have to start digging through the tree starting from

Configuration (Expand and then choose)
CN=Configuration,DC=Domain,DC=local (Normally this is your domain which will have a different name under Domain and Local, Expand and then choose)
CN=Services (Expand and then choose)
CN=Microsoft Exchange (Expand and then choose)
CN=First Organization (Expand and then choose)
CN=Administrative Groups (Expand and then choose)
CN=Routing Groups (Expand and then choose)
CN=Exchange Routing Group (GibberishNumber) (This will be different for each site.  Then expand and then choose)

In the Windows to the right you will see an Entry for each Send Connector you have.   Compare the names to the one you need to edit and double click that ONE.

Drill down until you find an entry called


Double click on it. It normally has no value and runs at Default settings (I don’t know the actual number, but it’s pretty unrestrictive)

Place a value from 1 or higher.  The Lower the number the fewer emails that are sent in a SINGLE SMTP CONNECTION to the Smarthost.  Click ok and close all of the Windows off.  Restart the Transport Service to ensure the new settings are picked up as well.

So if you have an ISP that restricts you to no more than say 30 emails in EACH SMTP connection (Exchange will send as many as you have be default) you’ll find either bad mail flow OR (most likely) you get dropped and have to explain yourself.  Embarassing and non productive.

With this change in, you have a way to keep outbound Mail flowing from Exchnage 2007 in a manner than keeps both YOU and the owner of the SmartHost happy.

And yes, I’m trying to write this into a Powershell script 🙂

And again, Exchange 2007 ONLY GETS THIS IN THE SCHEMA with SERVICE PACK 2 of Exchange Server 2007.

And again, a Special Thanks to Rick Lund-Pedersen of Around the Clock I.T. Solutions Inc for research into this issue and for finding the lost child.

Just keeping the mailflow on the go

The Energized Tech