IBM Support

TCPIP SMTP keeps resending garbage email

Question & Answer


Question

We had an incident today with a zOS TCPIP SMTP started task that sends outbound email from zOS to our mail servers. A batch job created an email yesterday at 10:52:33 and zOS SMTP issued these error message
when processing the Email :

EZA5212I 03/31/16 10:52:33 28Body:
EZA5214I 500 #5.5.1 command not
recognized
EZA5214I 500 #5.5.1 command not
recognized
EZA5214I 500 #5.5.1 command not
recognized
EZA5214I 500 #5.5.1 command not
recognized
EZA5214I 421 Exceeded bad SMTP command limit,
disconnecting.

Apparently zOS SMTP then forwarded the email to our mail server and the
customer's email mailbox every 20 minutes until we deleted the zOS
dataset that contained the email and stopped/restarted the TCPIP SMTP
started task.

After that TCP SMTP began processing several hundred email messages
that had been Queued up behind the bad email. Unfortunately we did
not save/rename the SMTP dataset that contained the bad email before
deleting so that data was lost. We do however have the email that
SMTP sent to the customer. It is supposed to contain a simple list of datasets but instead it contains 5MB of garbage data with a lot of
special characters and unreadable data in it.

Answer

I am sorry but there is no SMTP function available to stop the resending of the emails. At this point you have the options to first resolve the unrecognizable character issue that started the re-sends, or
you can do a periodic query of the mail backlog, and when it starts
growing check for the EZA5214I 500 command not recognized and
EZA5212I Data arrived while Sending Mail body issue as being the
cause for the backup.

But to be very clear: It is actually the receiver who is requesting the resend, not SMTP.
The receiver is saying hey; there is an error with this mail, please resend it... So TCP/IP SMTP is just doing what we are asked to do basically.

[{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SSSN3L","label":"z\/OS Communications Server"},"Platform":[{"code":"PF035","label":"z\/OS"}],"Component":"","Version":"","Line of Business":{"code":"LOB35","label":"Mainframe SW"}}]

Product Synonym

ZOSCS COMMSERVER

Document Information

Modified date:
17 May 2016

UID

dwa1271437