SMTP Connector Delivery Restrictions on Microsoft Exchange 2003

The company I work for focuses on Portal, Messaging, and Identity. While we implement a lot of solutions based on Sun technology, we do provide consultation and deploy technology from other vendors. 

As long as it's Portal, Messaging and Identity.

For messaging alone, we are pretty comfortable with Sun Java System Messaging Server, Microsoft Exchange, Zimbra, Postfix and Sendmail. 

Personally, I prefer Postfix over Sendmail. Our company used to provide email hosting based on Postfix, until we switched to Sun Messaging Server some time back. 

Interestingly enough, a teleco in Singapore is using Sendmail as their MTA with Exchange as their backend. I configured the Sendmail for them, with integration to TrendMicro Anti-Virus/Anti-Spam engine.

As for Microsoft Exchange, I start to like it with Exchange 2007 onwards. I like the architecture for the new releases. I can't say the same about Exchange 2000/2003 though. :)

Anyway, I received a call from my customer (a ministry) that the Delivery Restrictions on their newly migrated Exchange Server 2003 is not working. As they have not purchased a support contract with us, we are not able to make a trip on-site to quickly resolve the issue.

It took quite a while to pin-point what had actually gone wrong remotely. It turned out that a registry key was not turned on while the migration was carried out. It was a rather rush job then. See here for detailed information.

Connector restriction checking is turned off by default because it can significantly affect performance to expand distribution groups and check the restrictions for each message that passes through the system. If possible, turn on this setting on where it is necessary (for example, on the bridgehead server for the restricted connector).

HKEY_LOCAL_MACHINE/System/CurrentControlSet/Services/Resvc/Parameters/

On the Edit menu, click Add Value, and then add the following registry value:

Value Name: CheckConnectorRestrictions

Data Type: REG_DWORD

Radix: Hexadecimal

Value: 1

It slipped my mind then. 

But come to think of it again, isn't Microsoft all about user-friendliness?

Why is there no warning message after the "OK" button is clicked? Or at least an instruction to modify the registry right on top of the "OK" button? :)