Mail on z/OS

This topic describes how to configure the Simple Mail Transfer Protocol (SMTP) server, the Communications Server SMTP (CSSMTP) application, z/OS® UNIX sendmail, and popper.

CSSMTP is the strategic mail program for z/OS Communications Server and should be used for forwarding mail from your NJE network or from local applications that write mail to a JES spool file, using the existing SMTP batch interface to forward the mail to other gateway servers. CSSMTP provides the easiest and simplest solution for this purpose, and if you use the SMTP server (SMTPD) for this purpose only, you should consider replacing SMTPD with CSSMTP. For more information about CSSMTP, see Configuring the CSSMTP application.

SMTPD and Sendmail can run concurrently with CSSMTP and are available to receive mail from the SMTP network to TSO and z/OS UNIX users respectively. Sendmail can also send mail from remote POP clients, allowing the z/OS system to be used as a mail server. However, IBM® has issued a statement of direction indicating that these servers will be withdrawn in a future release. If you are not using these servers, you should not configure them because they will be withdrawn. If you are using them, see Withdrawal of SMTPD and sendmail.