Message not RFC compliant

Francis BIELSA - 07:11am, Jun 15 2020

Hello, 

We encounter this error when a series of more than 200 emails is sent from an AS400 I5/OS SMTP server to Mdaemon's SMTP Relay version 19.5.5 64bit routinely at the 200th email. 

This test was made with the same message and the same PDF attached. 

- Sending mail 199 : 

Thu 2020-06-11 13:55:21.383: Session 589855; child 0001 

Thu 2020-06-11 13:55:21.383: Accepting SMTP connection from 192.168.100.1:50151 to 192.168.100.3:25 

Thu 2020-06-11 13:55:21.387: --> 220 md.domain.com ESMTP Thu, 11 Jun 2020 13:55:21 +0200 

Thu 2020-06-11 13:55:21.389: <-- HELO '192.168.100.3'  Thu 2020-06-11 13:55:21.389: --> 250 domain.com Hello '192.168.100.3' [192.168.100.1], pleased to meet you 

Thu 2020-06-11 13:55:21.389: <-- MAIL FROM:<APPRO@domain.COM> 

Thu 2020-06-11 13:55:21.389: APPRO@domain.COM is an alias for xxxx@domain.com 

Thu 2020-06-11 13:55:21.452: --> 250 2.1.0 Sender OK 

Thu 2020-06-11 13:55:21.452: <-- RCPT TO:<salaux@xxxx.com> 

Thu 2020-06-11 13:55:21.454: --> 250 2.1.5 Recipient OK 

Thu 2020-06-11 13:55:21.454: <-- DATA  Thu 2020-06-11 13:55:21.459: Creating temp file (SMTP): e:\mdaemon\queues\temp\md50000021502.tmp  Thu 2020-06-11 13:55:21.459: --> 354 Enter mail, end with <CRLF>.<CRLF> 

Thu 2020-06-11 13:55:21.460: Message size: 32215 bytes 

Thu 2020-06-11 13:55:21.462: Passing message through AntiVirus (Size: 32215)... 

Thu 2020-06-11 13:55:21.519: *  Message non infecté ( aucun virus trouvé) analysé par (Cyren AV) (ClamAV) 

Thu 2020-06-11 13:55:21.519: ---- End AntiVirus results 

Thu 2020-06-11 13:55:21.532: Création du message successful: e:\mdaemon\queues\inbound\md50002070743.msg 

Thu 2020-06-11 13:55:21.532: --> 250 2.6.0 Ok, message saved 

Thu 2020-06-11 13:55:21.538: <-- QUIT  Thu 2020-06-11 13:55:21.538: --> 221 2.0.0 See ya in cyberspace 

Thu 2020-06-11 13:55:21.538: SMTP session successful (Bytes in/out: 32315/289) 

- sending mail 200 : 

Thu 2020-06-11 13:55:21.549: Session 589856; child 0001 

Thu 2020-06-11 13:55:21.549: Accepting SMTP connection from 192.168.100.1:25575 to 192.168.100.3:25 

Thu 2020-06-11 13:55:21.553: --> 220 md.domain.com ESMTP Thu, 11 Jun 2020 13:55:21 +0200 

Thu 2020-06-11 13:55:21.554: <-- HELO '192.168.100.3'  Thu 2020-06-11 13:55:21.555: --> 250 md.domain.com Hello '192.168.100.3' [192.168.100.1], pleased to meet you 

Thu 2020-06-11 13:55:21.555: <-- MAIL FROM:<APPRO@domain.COM> 

Thu 2020-06-11 13:55:21.555: APPRO@domain.COM is an alias for xxxx@domain.com 

Thu 2020-06-11 13:55:21.556: --> 250 2.1.0 Sender OK 

Thu 2020-06-11 13:55:21.556: <-- RCPT TO:<salaux@xxxx.com> 

Thu 2020-06-11 13:55:21.558: --> 250 2.1.5 Recipient OK 

Thu 2020-06-11 13:55:21.558: <-- DATA  Thu 2020-06-11 13:55:21.562: Creating temp file (SMTP): e:\mdaemon\queues\temp\md50000021503.tmp  Thu 2020-06-11 13:55:21.562: --> 354 Enter mail, end with <CRLF>.<CRLF> 

Thu 2020-06-11 13:55:21.563: Message size: 2 bytes 

Thu 2020-06-11 13:55:21.564: --> 550 5.6.0 Message is not RFC compliant; more than one "From" header 

Thu 2020-06-11 13:55:21.565: <-- QUIT  Thu 2020-06-11 13:55:21.565: --> 221 2.0.0 See ya in cyberspace 

Thu 2020-06-11 13:55:21.565: SMTP session terminated (Bytes in/out: 102/329) 

A test without "Refusing messages that do not respect the RFC standards" has been done without result. 

It seems that the AS400 server creates a new session for each mail and has no limitation of simultaneous sending. 

An idea  

Sincerely  

FB