PC NTMMTA: Limit of Seven Instances

• Microsoft Mail Multitasking MTA for Windows NT, version 3.5

SYMPTOMS

When you run the Mail Multitasking MTA for Windows NT (NT MMTA) as a service, and you manually start an eighth instance where some or all instances are configured for Single Postoffice, you will get the following error message:

   Error 2140: An internal Windows NT error occurred.

CAUSE

When the drive letters are selected for the instances, two drive letters are skipped between instances. This happens even if the instance is configured as a Single Postoffice instance.

For example, on a computer with one floppy drive A:\ and G:\ as the first available drive letter, the first instance of the Mail External program will use drive B:\ as the HomePO. Drives G:\ and H:\ will not be used. The next instance will use drive I:\ for the HomePO; the third instance will use L:\. The fourth instance will use O:\, the fifth R:\, the sixth U:\, and the seventh X:\. When you try to start the eighth instance, you will get the above error message.

WORKAROUND

Use only seven instance when you run the Mail External program as a service.

If you need to run more than seven instances, you can start additional instances by running the Mail External program as an application and use the DrivesDirectPO option to point to the skipped drive letters.

STATUS

Microsoft has confirmed this to be a problem in version 3.5 of Microsoft Mail Multitasking MTA for Windows NT. A fix for this problem is in development, but has not been regression-tested and may be destabilizing in production environments.

Contact Microsoft Product Support Services for more information on the availability of this fix.

MORE INFORMATION

The MMTA.TXT file, on the Setup disk, incorrectly states that you should to be able to start more than seven single-postoffice instances.

   2.6 Limits of External or Dispatch Services per Windows NT Computer
   -------------------------------------------------------------------
   If each service that is created is one which includes LAN/WAN
   connections to other postoffices, there is a maximum of 7 concurrent
   MMTA services that can be run on each Windows NT server. This is because
   each service maps one drive for its home postoffice and two for its
   dynamic range. If an eighth service is started, a Windows NT error 2140
   will be displayed by the Windows NT service manager.

   Note: If a service has the Single Postoffice Service option checked in
   the Microsoft Mail Service Manger, that service will only use one drive
   mapping.