Why do I see “Recorded error — Zero length SMTP status line” error?
PMDF is expecting the remote system to contain valid SMTP status code when it does not have it. This error can be found in your mail.log_current file as well as in debug files and TCPdump files. All SMTP status lines are required to begin with three digits, followed by a space or dash, then an optional status message. Having an SMTP status line containing no characters is a protocol violation. The usual suspect is an extra CR or LF just before a status. PMDF treats this as a temporary error and attempts to send the mail again. This is a problem on the server end (usually from firewall software, or some Exchange servers); however, PMDF can handle this broken behavior. All you need to do is specify the smtp_crlf or smtp_lf channel keyword rather than the default keyword smtp_crorlf (smtp is synonymous for the smtp_crorlf keyword), and PMDF no longer treats bare CRs as a terminator. A single CR or a single LF is treated as a “normal” character. Process Software recommends using the keywor
