Читать книгу Creation of Postfix Mail Server Based on Virtual Users and Domains - Dr. Hidaia Mahmood Alassouli - Страница 6

2. Description of the Project:

2.1 Main Objectives:

The main objective of this work is to create an email server that supports mail delivery to multiple virtual domains .Each email address will be authentic to only that domain, for example Bob@mtn.com and Bob@acme.com are two different accounts that each receives different emails.

When the mail server setup has been completed it must be able to:

 Receive and store emails for users.

 Support quota to keep the mailboxes to a reasonable size of choice.

 Let users retrieve emails through IMAP and POP3.

 Receive and forward email for users if they are authenticated.

 Offer a webmail interface to read emails in a web browser.

 Detect virus and spam emails and filter them out or tag them.

2.2 System Overview:

The project describes how to create an email server with virtual domains and virtual users (users who can not log into the system, they can only exist in a database).

Basic knowledge of the following components is required to successfully set up the server.

 MySQL (creating a database, granting access to users), this is a database system that stores information about the domains, the user accounts and email forwarding.

 SMTP (Postfix) this is a protocol used between mail servers to send email messages.

 POP3, IMAP the type used here is Courier-IMAP an alternative could be dovecot, this is a server that provides access to mail directories.

 Fedora (Linux), understanding the general system administration, using text editor, command line and reading log files.

The accounts are stored in a MySQL database .The domains will have separate name spaces, for example mail for Bob@acme.com and Bob@mtn.com will go to separate mailboxes. So the arrangement will be separate mailboxes for each virtual account.

The server will use a POP/IMAP server that supports multiple domains. In this arrangement the administrator need not create and maintain system accounts for email addresses on the server, instead he will configure Postfix to deliver mail to a local message store where each virtual email address can have its own mailbox file. The users then retrieve their messages through the POP /IMAP server.

In addition the server will be capable of quota support and scanning of spam and viruses (Mail Scanner, Spam Assassin). The database (MySQL) will be managed manually from the command line mysql shell or by a web based management tool (Postfixadmin) created for postfix, and the users access their emails through a web based email client interface client (Squirrelmail).The block diagram below (figure 1) illustrates the system.

Fig. 2.1 Server System Block Diagram

2.3 Main Server Components:

The mail server will be created with the following packages in Fedora core 5 operating system:

 Postfix -2.2.8-1.2.

 MySQL -5.0.18-2.1.

 Courier – Imap – 4.4.1-1.5.

 Courier – Authlib – 0.62.1- 1.fc5.

 Squirrelmail – 1.4.6.tar.bz2.

 PostfixAdmin – 2.3.3.tar.gz.

 Apache2 that comes by default with Fedora core 5.

 Mail Scanner-4.84.3-1.rpm.tar.gz.

 Install-Clam-0.96.5-SA-3.3.1 or any clamav package.

 SpamAssassin which comes by default with Fedora core 5.

 Fedora core 5 (Operating system).

 Compaq 610 laptop Intel core Duo 3GHz 2GB RAM 320 GB Hard Drive.

All packages used are the i386 types. It is assumed that Fedora core 5 and Mozilla Fire Fox have been successfully installed and support for HTTP and SMTP enabled with the Firewall turned off.