SMTP: How the Gateway Uses Memory

The information in this article applies to:

• Microsoft Mail Gateway to SMTP, version 3.0

SUMMARY

The SMTP gateway only uses conventional memory. To run the gateway, make sure that you have at least 375 kilobytes available.

For additional information, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q105290
   TITLE     : SMTP: Err Msg: Insufficient Memory

MORE INFORMATION

The gateway, SMTPGATE, uses two executables: SMTPGET and SMTPPUT. SMTPGET is spawned by SMTPGATE every two minutes (by default). SMTPGET is responsible for checking for mail destine for your SMTP environment: Outbound mail. SMTPPUT is only spawned by SMTPGATE when a request for connection to Port 25 is made to the gateway machine. SMTPPUT is responsible for mail destine to your Microsoft Mail environment: Inbound mail.

Both SMTPGET and SMTPPUT are spawned into memory: the actual C call is "Spawnlp." They do not overlay the memory addresses of SMTPGATE; they use their share of the largest executable conventional memory space. When each executable is finished sending mail, it is unloaded from memory. If you look in the log file, you can see the lines:

   spawning SMTPGET    This is where "spawnlp" is called.
   spawn(SMTPGET)=0    This is the return code to indicate that SMTPGET was
                       successful.

                  Bytes Per
Dependency      Record Multiple   Variable   Memory Req.   Files

Local users            37            50         1,850       ACCESS2.GLB

Dispatch networks      38             1            38       One Network
                                                            Connection

Dispatch postoffice    90             1            90       One Network
                                                            Connection

External networks      45             1            45       NETWORK.GLB

External postoffices  115             1           115       *.XTN

Gateways               83             1            83       MASTER.GLB

Gateway Maps           83             1            83       ADDR_MAP.CFG
                                                            or *.NME
                                                2,304

         Size of SMTPGATE         74,655 (for Novell's TCP/IP)
         Size of SMTPPUT          66,751
         Size of SMTPGET         107,251

         Total                   250,961

         Message Body space      Dependent on Header and Message size.
                                 250,961 plus message body space