Setting privacy flags
The PrivacyOptions (p) option allows you to
set certain ``privacy'' flags.
Many of them do not give you any extra privacy,
rather just insisting that client SMTP servers
use the HELO command before using certain commands
or adding extra headers to indicate possible spoof attacks.
The option takes a series of flag names; the final privacy is the inclusive ``or'' of those flags. For example:
O PrivacyOptions=needmailhelo, noexpnThis insists that the HELO or EHLO command be used before a MAIL command is accepted and disables the EXPN command.
For more information, see ``O--set option''.