CSSMTP compatibility test

CSSMTP is the replacement JES mailer for SMTPD. It has much improved performance and also improved standards compliance. CSSMTP rejects noncompliant mail messages that SMTPD accepts. Fix the programs that produce noncompliant mail messages because they will be rejected by subsequent mail gateways, even if they are accepted by z/OS® mailer.

You might not be able to identify all of the noncompliant mail messages that SMTPD accepts or all of the programs on your system that produce JES mail messages. Because you cannot fully re-create your mail workloads in a test environment, you might not be able to fully verify CSSMTP compatibility in a test environment.

To allow you to test CSSMTP in your production environment without disrupting your existing mail workloads, CSSMTP implements a compatibility test mode. In this mode, CSSMTP processes mail spool files but does not send the resulting mail messages. The only output of this test mode is error messages for noncompliant mail messages. You can run CSSMTP in test mode with SMTPD. The SMTPD handles your production mail workloads and CSSMTP in test mode verifies its compatibility with those workloads.