jorey bump qsdrjoreybumpcom hanspeter kunz wrote 02222008 0712 im trying rewrite received headers sasl authenticated senders order avoid mails classified spam sending dynamic ip experience unnecessary long servers ip blacklisted external sites wont block mail users dynamic ips server classifying spam ways avoid example users submit mail via port 587 requires authentication filtered thu 07 aug 2008 135130 0500 header_checks handled differently emails one recipient