What is it?
The double counting occurs when Postfix is used with an after queue content filter like Amavisd-new. The email passes through Postfix twice, once before handing off to the filter and then when the email is received back from the filter for final delivery or forwarding. Each passage through Postfix generates email log entries.
It is a known issue that Pflogsumm produced email statistics which were multiplied by two. No easy way of solving this in Pflogsumm is available. See https://jimsun.linxnet.com/downloads/pflogsumm-faq.txt FAQ 14.
This script sanitizes the log files to disregard the lines relating to the re-injection of the same message.
How do I get it?
The code for the project is hosted on github. Please see: PrePflog source code repository
Previous versions are archived for historical reference but are no longer maintained and should not be used: PrePflog previous versions
GPG signatures for the latest versions are available here PrePflog gpg signatures