Good day to you all,
today, I was setting up a postfix mail server. Everything works well: mails get forwarded from my server's mail address,
firstname.lastname@example.org, to my personal email
When testing with telnet, like this, I found that I could send mail only to
The thing is: My logs show me that I get connections from 'unknown'.
Here is a part of my
/var/log/maillog (default CentOS postfix log location. On other Linux systems possibly
Jun 2 22:58:31 vps postfix/smtpd: connect from unknown[A.B.C.D] Jun 2 22:58:31 vps postfix/smtpd: connect from unknown[A.B.C.E] Jun 2 22:58:43 vps postfix/smtpd: connect from unknown[A.B.F.G] Jun 2 22:58:55 vps postfix/smtpd: connect from unknown[A.B.F.H] Jun 2 22:58:58 vps postfix/smtpd: disconnect from unknown[A.B.C.D] ...
With my current ruleset, these unknown spambots should be completely unable to send their garbage on their way to the internet.
However, I would like to check if these unknowns actually got any mail sent from my server.
What I tried
I tried the
mailq command to check queued mails. This list was empty. However, this does not exclude that there was traffic.
Also, I checked my log with
cat /var/log/maillog | grep 'sent'. Zero matches. I am uncertain whether this means no bot could send spam or that postfix does not log sent mails from unknown's.
How can one check outgoing mail traffic with postfix?