sendmail, 4th Edition

PrivacyOptions

Increase privacy of the daemon V8.1 and later

The PrivacyOptions option is used primarily as a way to force other sites to adhere to SMTP conventions, but can also be used to improve security.

The forms of the PrivacyOptions option are as follows:

O PrivacyOptions=what,...                  ← configuration file (V8.7 and later)
-OPrivacyOptions=what,...                  ← command line (V8.7 and later)
define(`confPRIVACY_FLAGS',``what,...'')   ← mc configuration (V8.7 and later)
Opwhat,...                                 ← configuration file (deprecated)
-opwhat,...                                ← command line (deprecated)

Multiple what arguments are allowed but they must be separated from one another by commas^[406] (there can be arbitrary spaces around the commas). For example:

define(`confPRIVACY_FLAGS',``authwarnings, needmailhelo'')

If this option is entirely omitted or if no what arguments are listed, the option defaults to public. The default for the mc configuration technique is authwarnings. The possible what arguments are listed in Table 24-23, and are described in more details in the sections that follow.

Table 24-23. PrivacyOptions option keywords

Keyword	§	Meaning
authwarnings	PrivacyOptions=authwarnings on page 1066	Enable X-Authentication-Warning: headers.
goaway	PrivacyOptions=goaway on page 1066	Much checking for privacy and security.
needexpnhelo	PrivacyOptions=needexpnhelo on page 1067	Require HELO before EXPN.
needmailhelo	PrivacyOptions=needmailhelo on page 1067	Require HELO before MAIL From:.
needvrfyhelo	PrivacyOptions=needvrfyhelo ...