Deploy Postfix messaging System (i) protocols for messaging system roles and messaging systems

The mail system is not a single system, but consists of different components and functions, and in order to realize the communication of mail, it requires some protocol support (i.e. mail protocol).

The following is a brief description of the messaging system role and mail system protocols.

Role of the messaging system

MTA (Message transfer agent): Commonly referred to as mail Server Software, responsible for receiving messages sent by client software and transferring messages to other MTA programs, is a central part of the messaging system.

MUA (mail user agent): Commonly known as mail client software, is responsible for providing users with the interface of sending, receiving and managing e-mail.

MDA (Message Distribution Agent): The MDA software is responsible for distributing messages to the user's mailbox directory in the server, and is not user-oriented and is directly integrated into the MTA.

Mail Communication Protocol

SMTP (Mail Transfer Protocol): used primarily for sending and transporting messages, using TCP port 25th.

POP (Post Office Protocol): mainly used to collect mail from the mail server, using TCP port 110th.

IMAP (Internet Message Access Protocol): Also used for receiving mail, IMAP offers more flexible and powerful mail collection, mail management functions, using TCP port 143th.

Note: Only the e-mail client and the server support both SMTP and POP/IMAP protocols to enable full mail delivery and collection functionality.

Compiling and installing the Postfix mail system

1. Preparation work

To avoid port conflicts, program conflicts, and so on, you should deactivate the SendMail service from your system and set the default startup state to shut down. (Because the postfix system is compatible and follows some of the SendMail settings, it is recommended that you keep the SendMail package instead of uninstalling it directly)

In addition, in future articles need to explain postfix support SASL certification, so you should confirm that the package is installed.

[Root@localhost/] #rpm-qa | grep Cyrus

[Root@localhost/] #rpm-qa | grep db4-devel*

[Root@localhost/] #rpm-qa | grep pam-devel*

To enhance the rights control of the mail server, you need to create a dedicated run group account Postfix and Postdrop, as well as user account postfix.

[Root@localhost/] #groupadd-G 1200 Postdrop

[Root@localhost/] #groupadd-G 1000 postfix

[Root@localhost/] #useradd-M-u 1000-g postfix-g postdrop-s/sbin/nologin postfix

2 Compile and install Postfix

[Root@localhost Media] #tar zxf postfix-2.8.2.tar.gz-c/usr/src/

[Root@localhost Media] #cd/usr/src/postfix-2.8.2

Postfix software package configuration steps use "Make makefiles", the specific configuration options can refer to the source directory readme_files/under the documentation, if the use of Postfix support letter authentication, can refer to the file Sasl_readme information.

[Root@localhost postfix-2.8.2] #make makefiles ' CCARGS=-DUSE_SASL_AUTH-DUSE_CYRUS_SASL-I/USR/INCLUDE/SASL ' AUXLIBS =-L/USR/LIB/SASL2-LSASL2 '

The above configuration parameters are explained as follows:

Ccargs parameter: Provides additional extension parameters for the compiler. Columns such as: Enable SASL authentication, and point out that the CYRUS-SASL certification program's header file is located in/usr/include/sasl/.

Auxlibs parameter: Indicates to the compiler that an additional function library is outside the standard location. Columns such as: CYRUS-SASL certification program's library file is located in/usr/lib/sasl2/

[Root@localhost postfix-2.8.2] #make && make install//compile and install

After you execute the make install command, you will need to set some installed parameters in the final phase, and generally press ENTER to accept the default or automatically identifiable configuration.

After installation, you should perform the POSTCONF-A command to check the supported authentication method, if the output does not contain "Cyrus", you should check the configuration steps, correct the error after the configuration, compile the installation.

[Root@localhost postfix-2.8.2] #postconf-A

Cyrus//Support Cyrus Certification

Dovecot//Support DOVECOT Certification