How to troubleshoot SMTP connectivity issues and analyse log files


How to analyse MailEnable logging files and explains the various codes used in the log file.


MailEnable provides extensive logging of SMTP activity. There are 3 log files that are used by MailEnable. These are the debug, activity and W3C log. The W3C log files are essentially a replica of the Activity log, hence it is only necessary to investigate the activity and debug logs.

The debug log contains explanations of significant actions undertaken by MailEnable. For example, when a user attempts to relay a mail message, this is recorded and time stamped in the SMTP Debug log. The Activity log file contains a transcript of all SMTP commands exchanged between MailEnable and other remote clients or mail servers.

The simplest way to find a message and debug a SMTP transaction is to open the SMTP Activity log in notepad and search it.

It is also possible to load the log file into Micosoft Excel as follows:

How to import the Activity log into Excel:

  1. File > Open Browse to C:\Program Files\Mail Enable\Logging\SMTP (or equivalent directory).
  2. Change the Files of Type combo to All Files (*.*)
  3. Select the activity file to open (the files are named as SMTP-Activity-YYMMDD).
  4. Excels Text Import Wizard will now be displayed. Select the option to import the text as Delimited data and select Next
  5. Select the format as Tab delimited and select Next
  6. Select Finish to import the data

    A worksheet should be visible, with data represented as follows:

    A=Transaction date and time
    B=Transaction Type (Inbound or Outbound)
    C=Message ID/Message file Name (This is used to match with other logs to track messages)
    D=TCP/IP local socket number that the SMTP transaction was occurring on
    E=TCP/IP Address of the remote host involved in the SMTP transaction
    F=The name of SMTP Command that relates to the transaction
    G=The details for the SMTP Command that relates to the current transaction
    H=The details for the response to the SMTP Command that relates to the current transaction
    I=The number of bytes sent when executing this command
    J=The number of bytes received in executing this command

There are two important types of transactions outlined in the SMTP Activity log file. These are SMTP Inbound Transactions and SMTP Outbound Transactions. These transactions are denoted in the log files as SMTP-IN and SMTP-OU in their respective lines in the Activity log file.

How to relate Activity log entries to the debug log file:

The most obvious way of relating an entry in the Activity log file to the Debug log file is via the time stamp recorded in the file. It is also possible to use the Message ID (as this is often recorded in the debug log file). The message ID is useful in tracking messages as they pass through the MTA. The MTA logs this message ID and therefore you can use the logs to track a message as it is routed through MailEnable's Connectors via the MTA.

For example, a user may complain that they cannot send mail from Outlook. In this case an error message will be reported back to the remote mail client.

e.g. 503 This mail server requires authentication. Please check your mail client settings.

Use this error string to locate the transaction sequence in the SMTP activity log. Once the entry has been found in the SMTP activity log, check the SMTP debug log for the same time period. The system will record the reason why the relay request was denied.


How to use the MailEnable Log Analysis Tool to check  log files for errors:

How to configure where MailEnable stores its Log Files?:

Explanation of Socket Response and Error Codes used in MailEnable Log Files:

Product:MailEnable (All Versions)
Class:HOWTO: Product Instructions
Created:12/07/2003 2:54:00 PM
Revised:Wednesday, May 4, 2016