HP-UX Mailing Services Administrator's Guide

Sendmail 8.13.3
New Features in Sendmail 8.13.3
Chapter 3 125
A Mail Submission Program (MSP) is another instance of Sendmail that
is used for initial mail submission. MSP uses the /etc/mail/submit.cf
file as the configuration file. Sendmail 8.13.3 acts as an MSA or MTA
depending on the operational mode.
The default configuration starting with Sendmail 8.13.3 uses one
sendmail binary which acts differently based on the operation mode and
supplied options.
For security reasons, Sendmail must be a set-group-ID program to allow
for queuing mail in a group-writable directory. When Sendmail runs as a
set-group-ID program, the default group is smmsp and the group ID is
25.
The sendmail.cf configuration file is required for Sendmail to run as a
server and submit.cf configuration file is required to run Sendmail as a
mail submission program.
You must use the following permissions for the Sendmail configuration
and default queue files:
• -r-xr-sr-x root smmsp ... /PATH/TO/sendmail
This denotes that the owner of sendmail is root, the group is smmsp,
and the binary is set-group-ID.
• drwxrwx--- smmsp smmsp ... /var/spool/clientmqueue
This denotes that the client mail queue is owned by smmsp with
group smmsp and is group writable. The client mail queue directory
must be writable by smmsp. In the submit.cf file, you must set the
UseMSP option and you must set the QueueFileMode option to 0660.
• drwx------ root wheel ... /var/spool/mqueue
• -r--r--r-- root wheel ... /etc/mail/sendmail.cf
• -r--r--r-- root wheel ... /etc/mail/submit.cf
This section discusses the following topics:
• “Support for Secured Mail Transaction using STARTTLS” on
page 126
• “Cyrus SASL v2 Support” on page 127
• “The submit.cf File” on page 128