email message source ip

[fct]

Hello I have a client that every about 6 minutes try to send an email that is too large...
I would like to find what is the physical device that is trying to send this message.... the sender address is used by many devices.

How can I check this on the log files ?

Best regards

[liverpoolfcfan]

Before Bill asks, can you please post the output of "zmcontrol -v"

Can you explain a bit better. Is it an internal email going out that is causing the problem or an external email that is trying to come in?

How do you know about the failures? What errors have you seen?

[fct]

Thank you very much

zmcontrol -v
Release 8.0.7.GA.6021.UBUNTU12.64 UBUNTU12_64 NETWORK edition.

I notice that there is something wrong in the "Daily mail report"
in message reject detail I see
---------------------
MAIL
5.3.4 Message size exceeds fixed limit (total: 237)
237 localhost


In /var/log/zimbra.log there is these log

NOQUEUE: reject: MAIL from localhost[127.0.0.1]: 552 5.3.4 Message size exceeds fixed limit; proto=ESMTP helo=<mailservername.domainname.it>
connect from localhost[127.0.0.1]
NOQUEUE: filter: RCPT from localhost[127.0.0.1]: <>: Sender address triggers FILTER smtp-amavis:[127.0.0.1]:10026; from=<> to=<name@domain.com> proto=SMTP helo=<mailservername.domainname.it>
zimbra postfix/qmgr[4034]: 4949A7026BD: from=<>, size=2531, nrcpt=1 (queue active)
27FB4702681: client=localhost[127.0.0.1]


These messages happens about every 6 minutes
There is something strange in from (that is empty) and also in the message "size exceeds"

Best regards