Postfix: Log E-mails’ Subject

In Linux, you can view the statistics of incoming and outgoing E-mails by peeking into a log file called maillog (typically found in /var/log directory). Maillog provides the general information about the mails, for example, the sender and recipient(s), status – sent, rejected, bounced etc. I typically use maillog to check the destiny of mails. At times, it becomes difficult to spot a particular mail due to the sheer volume of mails being logged – especially on a production mail server.

For example: what if we need to check whether a particular mail sent by Person A has been delivered to Person B. Note that Person A might be sending lots of mails to Person B but we need to spot that one particular mail – say the one, which was sent by Person A but did not reach Person B. The only identifier, to identify a particular mail, in the maillog is the cryptic message ID. A better and more readable identifier would be the subject of an E-mail.Unfortunately, the subject of the mails is not logged, by default, in the maillog. But we can configure a mail server like Postfix to log the subject line. Read the rest of this entry »