Log in as superuser.
Create a group to which your system users will belong.
In the following example, the mail group is created:
# groupadd mail
Create the system user and associate it with the group you just created. In addition, set the password for that user.
In the following example, the user mailsrv is created and associated with the mail group:
# useradd -g mail mailsrv
useradd and usermod commands are in /usr/sbin. See UNIX man pages for more information.
You might also need to check the /etc/group and /etc/passwd files to be sure that the user has been added to the system group that you created.
Should you decide not to set up UNIX system users and groups prior to installing Messaging Server, you will be able to specify them when you run the 1.3 Creating the Initial Messaging Server Runtime Configuration.