Headerbottom, headerinc, headeromit Channel Options

From MsgServerDocWiki

Location of message header (headerbottom, headerinc, headeromit)

VMS MAIL only provides support for four message header lines: From:, To:, Cc: and Subject:. However, RFC 822 headers can contain many additional types of header lines. On OpenVMS systems, PMDF supports these additional header lines by optionally prepending or appending them to the message body whenever a message is delivered to a local user.

This behavior is controlled by the use of the headerinc, headeromit, and headerbottom channel options. The default is headerinc, which tells PMDF to prepend the header lines to the message. On OpenVMS systems, the channel option headerbottom, which tells PMDF to append the header lines to the end of the message, and headeromit, which tells PMDF to strip all header lines, are also available.

In some rare cases an SMTP server is used to deliver message content to something other than a proper mail user agent. Under these very rare circumstances it may be appropriate to omit header information or to place it at the end of the message, so these channel options are also supported for SMTP channels.

Extreme care should be taken not to use these options on channels connecting to other message handling systems --- relocating or eliminating message headers violates RFC 821 and RFC 822 and can lead to serious problems. Note also that many seemingly "bothersome" header lines may contain valuable information required to decode messages, track down problems, or even authenticate who really sent the message and thus thwart attempts at forging mail messages.