You install the Postfix server as a POSIX program package using the POSIX installation program (see the manual “POSIX Basics for Users and System Administrators”).
Installation requirements
To permit the installation and operation of the Postfix server, the PLAM library SINLIB.MAIL.nnn.POSTFIX must be available and shareable. The POSIX subsystem must have been started.
The Postfix server requires correctly functioning DNS functionality to provide error-free operation. As the server can be started automatically after installation has been completed, you should ensure that the DNS functionality is functioning correctly before beginning installation. You do this through correct configuration of the /etc/resolv.conf file and the DNS servers referenced there (see section “Configuring the DNS resolver”).
When MAIL:POSTFIX is installed, a check is made to see whether the /etc/resolv.conf file exists. The option is also available of taking over any existing configuration from $TSOS.SYSDAT.LWRESD.nnn.RESOLV.CONF or $TSOS.SYSDAT.SOCKETS.nnn.SOC6.RESOLV to a newly create /etc/resolv.conf.
If the DNS functionality is not functioning correctly, installation of the Postfix server can be delayed because of a DNS timeout, resulting in errored behavior of the Postfix server.
Starting installation
The Postfix server must run in privileged mode. You must therefore install the Postfix server using the POSIX installation command under the SYSROOT or TSOS ID (UID=0, GID=0):
| Start installation: Select the following function: Specify the following values in the screen which is then displayed: | |
IMON support?: |
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name of product: |
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package of product: |
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You can modify the installation path displayed for the installation procedure. However, it is advisable to keep to the default /opt/MAIL/postfix.
If another version of the interNet Value Edition delivery package is installed, the POSIX installation program issues a corresponding error message.
Postfix installation is fundamentally also possible when interNet Value Edition is already installed. However, in this case you must ensure that no sendmail daemon is active which contends with the Postfix server with regard to port number assignment. Generally this concerns port number 25.
> Abort Postfix installation by pressing the K2 key if you want to uninstall interNet Value Edition before installing Postfix.
> Continue Postfix installation by pressing the send key if you do not want to uninstall interNet Value Edition beforehand.
The POSIX installation program then checks whether the /opt file system has sufficient memory space and reads all the files from the PLAM library into the POSIX file system or generates references to PLAM library members. After all files have been read in, the POSIX installation program automatically starts a post-installation script which handles computerspecific configuration of the Postfix server.
Executing the post-installation script
The post-installation script performs the following steps:
First the post-installation script checks whether a POSTFIX user ID already exists.
If this is the case and the two conditions below are also satisfied, an error message is issued and execution of the post-installation script is aborted:
POSIX User Number
<=Default POSIX User NumberPOSIX Group Number
<=Default POSIX Group Number
If the POSTFIX user ID does not yet exist, the post-installation script sets up this user ID with the following attributes:
Random password
BS2000 account: SYSACC
Address space limit: 32 MB
Under POSIX this ID is assigned the home directory /var/empty and the login shell /bin/false as a login option is neither required nor desirable for the POSTFIX ID.
The post-installation script sets up a POSIX group MAILDROP.
If the NOBODY user ID does not yet exist, the post-installation script sets up this user ID with the following attributes:
Random password
BS2000 account: SYSACC
Address space limit: 32 MB
Under POSIX this ID is assigned the home directory /var/empty and the login shell /bin/false as a login option is neither required nor desirable for the NOBODY ID.
In the startup file /etc/profile of the POSIX shell, the PATH specification for the user with the user number 0 (SYSROOT or TSOS) is extended by the directories <installation-path>/bin and <installation-path>/sbin. If a C shell (csh or tcsh) is installed, the post-installation script proceeds analogously with the csh startup file (/etc/.login or /etc/csh.login).
If the default job class for batch jobs of the SYSROOT ID has a JOB-CLASS-LIMIT
<20, a warning is issued.If ADDRESS-SPACE-LIMIT < 32 MB applies for SYSROOT, a warning is issued.
If ADDRESS-SPACE-LIMIT < 32 MB applies for POSTFIX, a warning is issued.
If no POSIX-RLOGIN-DEFAULT is set for POSTFIX, a corresponding error message is output.
If SYSROOT has no read permission for the installation library (e.g. SINLIB.MAIL.nnn.POSTFIX), a corresponding error message is output.
The post-installation script attempts to determine the system’s domain name by inspecting the DNS Resolver configuration files /etc/resolv.conf and $TSOS.SYSDAT.SOCKETS.nnn.SOC6.RESOLV or $TSOS.SYSDAT.LWRESD.nnn.RESOLV.CONF .
The post-installation script sets the following parameters in the Postfix configuration file /etc/postfix/main.cf by calling postconf -e: mailq_path, newaliases_path, daemon_directory, readme_directory, html_directory, command_directory, sendmail_path, manpage_directory, mail_owner, setgid_group, config_directory and queue_directory. If a domain was found in step 11, the mydomain parameter is also set.
The post-installation script calls Postfix’s own post-installation script /etc/postfix/post-install.
If initial installation of Postfix is concerned, i.e. no configuration backup directory /etc/postfix.sav for a previous Postfix installation exists, the post-installation script checks whether a /etc/mail/aliases or /etc/aliases file exists. If one of these files exists, the postinstallation script copies the first file found to /etc/postfix/aliases and enters the following parameter definitions in the /etc/postfix/main.cf file:
alias_maps = hash:/etc/postfix/aliasesalias_database = hash:/etc/postfix/aliasesIf no serious errors are detected, the post-installation script uses /etc/init.d/MAIL.postfix start (depending on the answer to the installation query AutoStart-Postfix) to call the general POSIX start script for Postfix, and this starts the Postfix server under SYSROOT.
The /etc/init.d/MAIL.postfix script automatically determines the maximum values for JOB-CLASS, ACCOUNT, START and MAXIMUM CPU LIMIT which are permissible for SYSROOT. The script uses these values to start an enter job with the job name POSTFIX.
The Postfix server logs important messages in the /var/adm/syslog file using the syslog mechanism. In addition, the Postfix server records problems which occur when the enter job starts in the var/adm/postfix_startup.log file.
Completing installation
After successful installation, perform the possiblyremaining activities which are required in the POSIX shell under the TSOS ID. To do this, start the POSIX shell under the TSOS ID using the BS2000 command /START-POSIX-SHELL.
Files and directories used by the Postfix server
The table below lists the most important files and directories used by the Postfix server. If you use an installation path which differs from the standard Postfix installation path, the path names specified in the table must be adjusted accordingly.
Name | Type | Explanation |
/opt/MAIL | Directory | |
/opt/MAIL/postfix | Directory | Standard Postfix installation directory |
/opt/MAIL/postfix/bin | Directory | Links to Sendmail compatibility program |
/opt/MAIL/postfix/bin/mailq | Link | Outputs the mail queue |
/opt/MAIL/postfix/bin/newaliases | Link | Updates the alias index file |
/opt/MAIL/postfix/libexec/postfix | Directory | Daemon programs |
/opt/MAIL/postfix/libexex/postfix/local | Program | Local Delivery Agent |
/opt/MAIL/postfix/libexec/postfix/master | Program | Central administration program |
/opt/MAIL/postfix/libexec/postfix/pickup | Program | Processes mail selected locally |
/opt/MAIL/postfix/libexec/postfix/qmgr | Program | Queue management |
/opt/MAIL/postfix/libexec/postfix/smtpd | Program | Receipt of mails using SMTP |
/opt/MAIL/postfix/libexec/postfix/smtp | Program | Forwards mails using SMTP |
/opt/MAIL/postfix/readme | Directory | Online documentation |
/opt/MAIL/postfix/sbin | Directory | Management programs |
/opt/MAIL/postfix/sbin/postalias | Program | Generates/inquires the alias index file |
/opt/MAIL/postfix/sbin/postcat | Program | Outputs files in queues |
/opt/MAIL/postfix/sbin/postconf | Program | Displays/modifies Postfix parameters |
/opt/MAIL/postfix/sbin/postdrop | Program | Writes mails in the maildrop directory for delivery by Postfix |
/opt/MAIL/postfix/sbin/postfix | Program | Starts/stops the Postfix system |
/opt/MAIL/postfix/sbin/postmap | Program | Generates/inquires the index files |
/opt/MAIL/postfix/sbin/postqueue | Program | Queue management by the system administrator |
/opt/MAIL/postfix/sbin/postsuper | Program | Grants the system administrator superuser access to queues |
/opt/MAIL/postfix/sbin/sendmail | Program | Sendmail compatibility program |
/opt/MAIL/postfix/share | Directory | Online documentation in the form of man pages |
/etc/postfix | Directory | Directory for Postfix configuration files |
/etc/postfix/master.cf | Text file | Configuration for master daemon |
/etc/postfix/main.cf | Text file | Central Postfix configuration file |
/var/spool/postfix | Directory | Directory for queues and lock files |
/var/mail | Directory | Directory for mailboxes |
/var/mail/USER | Mailbox file | Mailbox for the user USER |
/etc/rc0.d/K17MAIL.postfix | Link | Link to start/stop script |
/etc/rc2.d/S97MAIL.postfix | Link | Link to start/stop script |
/etc/init.d/MAIL.postfix | Script | Start/stop script |
Uninstalling the Postfix server (SMTP server)
Uninstall the Postfix server using the POSIX installation command under the SYSROOT or TSOS ID (UID=0, GID=0):
| Start uninstallation: Select the following function: In the subsequent screen display mark the line containing the following values and activate your selection by pressing the send key:
| |
| Follow the further instructions issued by the tool. |
If Postfix configuration files have been modified since the time installation took place, these files are saved in the /etc/postfix.sav directory. When POSIX is installed again later, the files in the backup directory /etc/postfix.sav are used instead of the standard configuration files supplied.