Diagnosing Simple Mail Transfer Protocol (SMTP) problems

The Simple Mail Transfer Protocol (SMTP) is used to transfer electronic mail reliably and efficiently. Recipients of the mail can be users on a local host, users on Network Job Entry (NJE), or users on remote TCP/IP hosts. The SMTPNOTE command is used to the send mail to a local or remote host.

This topic describes how to diagnose problems with SMTP and contains the following subtopics:

Sender SMTP
Receiver SMTP
SMTP environment
SMTP definitions
Diagnosing SMTP problems
ADDRBLOK data set
SMTP RESOLVER trace

For information about diagnosing problems with the other z/OS® Communications Server mail application, z/OS UNIX sendmail, see Diagnosing z/OS UNIX sendmail and popper problems.