> Hello, I want write rule to block mail with "Subject: Re" , and don't have "In-Reply-To:" I try this if /Subject: Re:/ !/In-Reply-To:/ REJECT sorry no spam. endif And this: if !/In-Reply-To:/ /Subject: Re:/ REJECT sorry no spam. endif But don't work properly. It works exactly as documented in the header_checks manual page.