sendmail, 4th Edition

Alphabetized sendmail Macros

The sendmail program reserves all lowercase letters, punctuation characters, and digits for its own use. For multicharacter names, it reserves all those that begin with an underscore or a lowercase letter. Table 21-7 lists all the macro names that have special internal meaning to sendmail. Included in this list are macros that are used by the mc configuration technique.^[312]

Table 21-7. Reserved macros

Macro	§	Description
$_	$_ on page 801	RFC1413-validation and IP source route
$a	$a on page 802	The origin date in RFC822 format
${addr_type}	${addr_type} on page 803	Is address recipient/sender header/envelope
${alg_bits}	${alg_bits} on page 804	The number of bits in the TLS cipher
${auth_authen}	${auth_authen} on page 804	RFC2554 AUTH credentials
${auth_author}	${auth_author} on page 805	RFC2554 AUTH= parameter
${auth_ssf}	${auth_ssf} on page 806	AUTH encryption key length
${auth_type}	${auth_type} on page 806	Authentication mechanism used
$b	$b on page 807	The current date in RFC2822 format
${bodytype}	${bodytype} on page 808	The ESMTP (Extended SMTP) BODY parameter
$B	$B on page 808	The BITNET relay (mc configuration, deprecated)
$c	$c on page 808	The hop count
${cert_issuer}	${cert_issuer} on page 809	Distinguished name of certificate signer
${cert_md5}	${cert_md5} on page 809	MD5 of cert certificate
${cert_subject}	${cert_subject} on page 809	The cert subject
${cipher}	${cipher} on page 809	Cipher suite ...