if /^\s*Received:.*Authenticated sender.*\(Postcow\)/ /^\s*Received:.*Authenticated sender:(.+)/ REPLACE Received: from localhost (localhost [127.0.0.1]) (Authenticated sender:$1 /^\s*User-Agent/ IGNORE /^\s*X-Enigmail/ IGNORE /^\s*X-Mailer/ IGNORE /^\s*X-Originating-IP/ IGNORE /^\s*X-Forward/ IGNORE endif