The 'SMTPEXTAUTH.TAB' file enable the AfterLogic XMail Server administrator to use external authentications methods to verify SMTP clients. If the 'SMTPEXTAUTH.TAB' does not exist, or it is empty, AfterLogic XMail Server standard authentication methods are used, and those will use either the 'MAILUSERS.TAB' or the 'SMTPAUTH.TAB' to verify account credentials. If the file 'SMTPEXTAUTH.TAB' is not empty, then the AfterLogic XMail Server standard authentication methods are not advertised in the AUTH response of the EHLO SMTP command. Instead, only the ones listed inside the 'SMTPEXTAUTH.TAB' are reported to the SMTP client. The 'SMTPEXTAUTH.TAB' file can contain multiple lines with the following format:
"auth-name"[TAB]"program-path"[TAB]"arg-or-macro"...[NEWLINE]
This file can contain multiple lines whose 'auth-names' are listed during the EHLO command response. Where 'arg-or-macro' can be (see [MACRO SUBSTITUTION]):
authentication method (PLAIN, LOGIN, CRAM-MD5, ...)
SMTP client supplied username (available in PLAIN, LOGIN and CRAM-MD5)
SMTP client supplied password (available in PLAIN and LOGIN)
challenge used by the server (available in CRAM-MD5)
client response to server challenge (@CHALL - available in CRAM-MD5)
a file path where the external authentication binary might supply extra informations/credentials about the account (available in all authentications)
The RFILE file is composed by multiple lines with the following format:
VAR=VALUE
Currently supported variables inside the RFILE file are:
Supply SMTP permissions for the account (see [SMTPAUTH.TAB] for detailed inforamtion)
Example:
"PLAIN" "/usr/bin/my-auth" "-a" "@@AUTH" "-u" "@@USER" "-p" "@@PASS" "-r" "@@RFILE"
The external authentication binary may or may not fill a response file. If the authentication has been successful, the binary should exit with a code equal to zero. Any other exit code different from zero, will be interpreted as failure.