Sam Jones: > Now, if I manually strip the line endings \r\n and replace them a plain > newline \n, it works perfectly suggesting something strips the line > endings if the are \r\n after it has been signed.
This happens when you use an old Postfix version AND have MIXED line endings (some lines end in <LF>, other lines end in <CR><LF>). Two solutions: A) Use consistent line endings: ALL lines end in <LF>, or ALL lines end in <CR><LF>. B) Upgrade to a Postfix 2.9 or later that strips <CR><LF> regardless. as described in the manpage entry below. Wietse sendmail_fix_line_endings (default: always) Controls how the Postfix sendmail command converts email message line endings from <CR><LF> into UNIX format (<LF>). always Always convert message lines ending in <CR><LF>. This setting is the default with Postfix 2.9 and later. strict Convert message lines ending in <CR><LF> only if the first input line ends in <CR><LF>. This setting is backwards-compatible with Postfix 2.8 and earlier. never Never convert message lines ending in <CR><LF>. This setting exists for completeness only. This feature is available in Postfix 2.9 and later.