Issue Postfix malfunctioning

[EnriqueR]

Server operating system version

Ubuntu 24.04.1 LTS

Plesk version and microupdate number

18.0.65 #1

My Plesk server suddenly alerted me to a mass mailing via an account correo@email.com. I went into the maillog file and saw that it was triggered by the following line:

Nov 25 08:31:27 servidor postfix/smtpd[2264977]: 82EF8863DF: client=localhost.localdomain[::1], sasl_method=PLAIN, sasl_username=user@localdomain.com
Nov 25 08:31:27 servidor psa-pc-remote[1929837]: 82EF8863DF: from=<user1@externaldomain1.com> to=<user2@externaldomain2.com>
Nov 25 08:31:27 servidor postfix/cleanup[2265531]: 82EF8863DF: message-id=<74c40b760a1465d00728c64842d37394@externaldomain1.com>
Nov 25 08:31:27 servidor psa-pc-remote[1929837]: 82EF8863DF: py-limit-out: stderr: DATA CHMFROM:user@localdomain.com
Nov 25 08:31:27 servidor psa-pc-remote[1929837]: 82EF8863DF: py-limit-out: stderr: INFO:__main__:Envelope sender was changed from 'user1@externaldomain1.com' to 'user@localdomain.com'
Nov 25 08:31:27 servidor psa-pc-remote[1929837]: 82EF8863DF: py-limit-out: stderr: INFO:__main__:Address in header 'From: Joaquim Miranda <user1@externaldomain1.com>' was changed to 'user@localdomain.com'
Nov 25 08:31:27 servidor psa-pc-remote[1929837]: 82EF8863DF: py-limit-out: stderr: INFO:__main__:Setting 'X-PPP-Vhost' header to 'localdomain.com'
Nov 25 08:31:27 servidor psa-pc-remote[1929837]: 82EF8863DF: py-limit-out: stderr: PASS
Nov 25 08:31:27 servidor psa-pc-remote[1929837]: 82EF8863DF: spf: stderr: PASS
Nov 25 08:31:27 servidor psa-pc-remote[1929837]: 82EF8863DF: check-quota: stderr: SKIP
Nov 25 08:31:27 servidor postfix/qmgr[1252659]: 82EF8863DF: from=<user@localdomain.com>, size=1335849, nrcpt=1 (queue active)

As you can see, suddenly the incomming email user1@externaldomain1.com was changed to user@localdomain.com

How could this happen? I have enabled the option ‘Correct incorrectly set senders for outgoing mail’.

It is very strange because my server received an email from an external email user1@externaldomain1.com to another external email user2@externaldomain2.com and my server has converted the sender to an internal email user@localdomain.com and is trying to send it.

 

[EnriqueR]

Solved. For some reason in webmail, identities, it was registered user1@externaldomain1.com

 

[mow]

Nov 25 08:31:27 servidor postfix/smtpd[2264977]: 82EF8863DF: client=localhost.localdomain[::1], sasl_method=PLAIN, sasl_username=user@localdomain.com

As you can see, suddenly the incomming email user1@externaldomain1.com was changed to user@localdomain.com

How could this happen? I have enabled the option ‘Correct incorrectly set senders for outgoing mail’.

And that's exactly what it does.
Your user authenticated as user@localdomain.com, and then tried to send as user1@externaldomain1.com. Which was corrected to the address the user authenticated with.