Some applications, especially those forwarding or replying using existing message text, can provide additional message headers as plain text within the body of the message. The special logical PMDF_RELAYING can be used to instruct PMDF to read additional headers from the top of the message's body.

PMDF_RELAYING is also used to construct an additional Received: header line. The translation of PMDF_RELAYING is placed on the Received: line along with the current date and time. The result should conform to RFC 822 conventions for Received: lines; PMDF does not check to insure that this is the case, however.

The additional Received: header will not be generated if PMDF_RELAYING translates to a single space character.

Nonprivileged use of PMDF_RELAYING presents a security hole --- users could use this mechanism to forge message headers. For this reason PMDF_RELAYING must be defined as an executive mode logical in order to have any effect. This precludes its use by nonprivileged users, yet makes it available to the system-level applications that might actually need it.

Under no circumstances should PMDF_RELAYING be defined system-wide --- it will interfere with the use of PMDF by normal users.