Sendmail, 3rd Edition

Chapter 21

Section 21.4.2	Prior to V8.10, the maximun length of a multicharacter macro name was 20 characters. As of V8.10, it is now 25 characters.
Section 21.8	Prior to V8.10, loops in macro definitions could cause sendmail to appear to hang and to eventually segmentation-fault and core-dump. As of V8.10, the loop is detected and an error is reported instead.
Section 21.9	Since V8.8, many new macros have been introduced. Some deal with authentication, while others store handy values that you can use in rule sets. All the new macros are listed in Table B-2.
$k	V8.10 no longer supports the TRUST_POPEN compile-time macro.

Table B-2. New macros

Macro name	§	Version	Contains as its value
${addr_type}	${addr_type}	8.10	A value that says whether the current address is one of a sender or a recipient
${alg_bits}	${alg_bits}	8.11	The number of bits in the TLS cipher
${auth_authen}	${auth_authen}	8.10	The authentication credentials that were approved as its value
${auth_author}	${auth_author}	8.10	The address that followed the MAIL FROM: AUTH= extension
${auth_ssf}	${auth_ssf}	8.11	The SASL encryption-keylength
${auth_type}	${auth_type}	8.10	The actual type of encryption used
${cert_issuer}	${cert_issuer}	8.11	The Distinguished Name (DN) of the certificate authority
${cert_md5}	${cert_md5}	8.12	The result of an md5(1) 128-bit “fingerprint” of the certificate
${cert_subject}	${cert_subject}	8.11	The DN of the certificate
${cipher_bits} ...