Since Majordomo is responsible for managing email lists, Majordomo must be tightly integrated with a MTA.
Each MTA discussed can be configured by editing a configuration file. For Sendmail, you can configure sendmail.cf; this file is usually located in /etc/ or /etc/sendmail. For Exim, you can configure exim.conf; this file is usually located in /etc/exim/. For Postfix, you can configure main.cf; this file is usually located in the /etc/postfix/ directory. If your MTA configuration file is not in one of these locations on your system, you should consult the documentation that came with your operating system or search for the file with find. For example, to find the sendmail.cf on your system, use the command
[root@majordomohowto ~]# find / -name sendmail.cf -print
Alternatively, some administrators do not want to edit the sendmail.cf file directly. It is possible to use M4 macros to create the sendmail.cf from a file (usually sendmail.mc in /etc/) that contains the necessary information to generate the sendmail.cf. The purpose of the M4 configuration is to provide an easy way to create the sendmail.cf file. The idea is that the file using the M4 macros is easier to understand than the sendmail.cf file. By running the m4 preprocessor, a sendmail.cf file can be generated. For example, to generate /etc/sendmail.cf from /etc/sendmail.mc, you would use the command
[root@majordomohowto etc]# m4 /etc/sendmail.mc > /etc/sendmail.cfWhen referring to the file used to generate sendmail.cf, I assume that the file is called sendmail.mc.
MTAs are usually programmed to make it difficult for people to create "perfect" forgeries of email. For example, when a user sends a message via SMTP, the source IP address is typically logged, and when a user sends a message by giving it directly to the MTA, the MTA will usually put a warning message in the header specifying the user who really sent the message. However, some programs need to be able to send messages masquerading as other users, and having this extra security line appended to the header is annoying. MTAs usually handle this problem by having trusted users. In order for Majordomo's resend script to work properly, majordom must be a trusted user since the program needs to resend mail from other users.
If you would like to edit Sendmail's configuration file directly, add the line
Tmajordomoto the sendmail.cf file.
If you prefer to use M4 macros, add the following line to your sendmail.mc file, and regenerate sendmail.cf.
define(`confTRUSTED_USERS',`majordomo')
In exim.conf, look for a line similar to
trusted_users = mailIf the line exists, add majordom as a trusted user. Note that Exim separates items in a list with a ":" and no whitespace. The modified line should look similar to
trusted_users = mail:majordomIf the line does not exist, add the line
trusted_users = majordomto the main configuration section (the first part) of exim.conf.
Postfix does not have untrusted users; therefore, it is not necessary to make Majordomo a trusted user under Postfix.