We find FREEMAIL_REPLYTO to be quite successful at weeding out spam so we raised up to 9.1. i.e. with this in local.cf:
score FREEMAIL_REPLYTO 9.1 However, it causes a false positive with FREEMAIL_REPLYTO and it got me very curious: Here's a sanitized minimal example that triggers this (indented by 4 spaces): Date: Wed, 8 Mar 2017 03:20:05 +0000 (UTC) From: Winston <some...@yahoo.com> To: Kipper <u...@example.com> Subject: foo Reply-To: Winston <some...@yahoo.com> > From: Kipper <u...@example.com> > To: Winston <some...@yahoo.com>, innocentbystan...@ymail.com > Subject: bar Reports: * 9.1 FREEMAIL_REPLYTO Reply-To/From or Reply-To/body contain different * freemails The problem is caused by innocentbytan...@ymail.com IN THE BODY! This seems a bit overzealous. It seems like a bit of an over-reach to look at headers in the BODY of the message. This is an excellent rule except for this rude message body cavity search! I suggest only searching the headers in this rule. If you really feel it aught to search the body like this, can you please split it into 2 rules: 1) the existing rule which searches the body+headers, and 2) a second that only searches the headers.