Functionality System Mailbox in exchange server 2003

This article gives you the functionality of the built in system mailbox that present in the mailbox store. Every private information store in Exchange Server 2003, has 3 system mailbox by default.

The following are the three different system mailboxes are:

•SystemMailbox{GUID}
•System Attendant Mailbox
•SMTP Mailbox

System Mailbox {GUID}:

•Contains two parts to each System mailbox – the mailbox itself with its content in the corresponding information store and an associated directory object located in MESO (Microsoft Exchange System Object) folder in AD.
•GUID is related to the objectGUID i.e., to the system mailbox. The objectGUID of the mailbox store with which the system mailbox is associated.
•Whenever we mount the store, it checks for the availability of the systemmailbox{GUID}. If not it looks in the MESO directory for the same.
•Each MDB has its own GUID associated with a particular instance of SystemMailbox{guid}.
•Faulty functioning SystemMailbox{guid} then, there’s a very good chance EXOLEDB event sinks will not function.
•It will occupy some reasonable amt of space for storing the schema definitions.

System Attendant Mailbox:

•Each Exchange 200x server has one (and hopefully only one) System Attendant mailbox
•The System Attendant Mailbox contains the folder SpecialPrivateFolderForFreeBusyStorage, for Free/Busy information for Microsoft Outlook and CDO Applications (Collaboration Data Objects) which will be temporarily stored in MSExchangeFBPublish.
•The System Attendant Mailbox will also be used to send and receive Exchange monitoring messages for the Link Monitoring Service. You can find this function in the Exchange System Manager under Tools – Monitoring and Status.
•System Attendant mailbox is also required to be available during mailbox moves. For instance, if you have the mailbox store containing the System Attendant mailbox dismounted during a mailbox move, the move will fail.
•There are two parts to make up the complete System Attendant mailbox: a directory object and a mailbox object.
•Faulty system attendant mailbox, results in OWA-generated Free/Busy information not getting updated and also mailbox moves fail.

SMTP Mailbox

•The SMTP mailbox will be generated when the private information store is created and mounted.
•SMTP (servername-{guid}) mailbox is used by the mail transport of Exchange 200x as a temporary holding place for various messages as they pass through the system. In other words, every private mailbox store contains an SMTP mailbox to store temporary messages.
•For eg, The folders MTS-IN and MTS-OUT are used by Exchange Deployment Kit (EDK) connectors to transfer messages between the MTA (Microsoft Exchange Transport Agent) and the Exchange Server information store (store.exe). They are also used for X400 connectors, Exchange site connectors, and fax connectors.
•Faulty SMTP mailbox, results in failure in delivery into the store

Logging into system mailbox:

Logging into the system mailbox is not recommended, but still we can open the mailbox using the MFCMAPI.