DOCUMENT:Q131150 27-OCT-1999 [pcmail] TITLE :SMTP: Causes of Hangs on Mail Gateway to SMTP PRODUCT :Microsoft Mail For PC Networks PROD/VER:MS-DOS:3.0 OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Mail Gateway to SMTP, version 3.0 ------------------------------------------------------------------------------- SUMMARY ======= Once the Microsoft Mail Gateway to SMTP is functional, several factors still need to be addressed before the gateway can be expected to perform reliably. If these factors are overlooked, the gateway may intermittently hang and refuse inbound connections. The configuration issues listed below are usually involved if the gateway stops working with no error messages recorded in the SMTPGATE.LOG file, and the following message is repeatedly displayed in this file: Spawning SMTPGET Spawn(SMTPGET)=0 Idling: 48258 bytes, largest 47234 MORE INFORMATION ================ The following five configuration issues are known for hindering the reliability of the SMTP gateway. 1. Postoffice (PO) and Gateway should be on the same physical network. Because the gateway's temporary files are written on the postoffice (M:\MAILDATA\SMTP\), and not its local hard disk, the performance of the gateway is dependent on file input/output. The most effective way to ensure fast file input/output is to have both the gateway and postoffice on the same physical network. 2. Use a Mail Relay Host for inbound SMTP mail. It is not mandatory to have Mail Relay Host configured for inbound mail, but it is highly recommended. Because the SMTP gateway is dependent on a DOS redirector, and the reliability of a UNIX to DOS connection is not as robust as the reliability of a UNIX to UNIX connection (UNIX is multithreaded; DOS is single threaded), it is recommended to control the required UNIX to DOS connection by storing all messages destine for MS Mail on a Host before they get forwarded to MS Mail. In other words, the Mail Administrators need to have as much control over the less reliable UNIX to DOS connection as possible. The optimum way to control this is by putting a Mail Relay Host on the same network segment as the gateway and PO server. Not only does this increase the reliability of the UNIX to DOS connection from a physical perspective, but it allows the Host to be configured to open/close the connections more effectively. 3. Have routers use static routing. If the Smart Host (Mail Relay Host) is not on the same network segment as the gateway and PO, then static routes should be configured on the router that separates the gateway and host. The IP addresses for the Gateway and the Smart Host should be added to the static table on the router. NOTE: Most routers use dynamic routing by default; a static table needs to be manually created and maintained. 4. Use a 16-bit Network Interface Card (NIC). You should use a 16-bit NIC to get fast file input/output. Additionally, it is recommended to use a 16-bit NIC with the RAM disabled. 5. Use one protocol per NIC (IPX/SPX). When the postoffice is on a Novell NetWare server and IPX/SPX is used to access the postoffice when TCP/IP is used to access the Host, it might be necessary to isolate each protocol on a separate NIC. For additional information, please see the following article in the Microsoft Knowledge Base: Q101461 Microsoft Mail SMTPGATE.EXE Version 3.0.9 Update Additional query words: ====================================================================== Keywords : Technology : kbMailSearch kbMailGateSearch kbZNotKeyword3 kbMailGateSMTP300 Version : MS-DOS:3.0 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 1999.