| Our world has stepped into information times, and Email services are becoming one of the most important applications because of their prompt and convenient characteristics. Users can contact Internet users of the world's any corner with a very low price and a very rapid way by web e-mail system since we need only to pay telephone and net charges wherever messages are sent, and messages can be sent to any destination of the world what you have designated in a few seconds. These email messages may be a variety of forms such as Text, images, sounds. And, users can receive a great deal of free news and Emails, achieving comfortable information retrieve, which has outperformed any traditional ways. Email has been used extensively due to its simpleness, rapid mailing, cheap charge, convenient conservation and fast traffic in the seven seas. It has changed dramatically people's communication ways. In addition, email also can deliver message by one-to-many. In other words, same emails can be sent to many persons once time. The most important point is that email is system of information communication from entire Internet network to facing directly person to person in the whole other systems, and its objects of sending and receiving messages are persons, which has greatly satisfied the needs between people and people.But there are a lot of enterprises and institutions without their own Email system at present in our country, and High price of specialized mail system has made enterprises hard to afford. I design the Email system based on Qmail under Linux platform which offers the reliable and gratis mail service for enterprises and institutions.In terms of stability and safety we analyze and compare many mail server systems characteristic, then select a suitable Plan and mail server. Finally Linux has been chosen as the platform, and Qmail as the mail system of MTA.Qmail is absolutely free. Anyone can freely download, spread and use the software according to its copyright notice. Efficiency and concision of Qmail design can reduce greatly the hardware requirements of the mail server. This is also a corresponding reduction in the hardware cost. Qmail is a free hsoftware tat complies with GPL copyright notice. The meaning of freedom not only means that the use of the software itself is free, but also means that anyone can optionally modify its source code to suit different needs.Linux openness is that system needs to follow the standard of the world, especially open system internet (OSI) international standards. All the hardware and software with following the international standards can be compatible with each other and can easily achieve interconnection. It is a multi-user, multi-tasking system. Linux is superior to other operating systems that can not be connected closely together with the core of the network and are inflexible in built-in networking features in the communications and network functions. However, Linux can provide users with comprehensive and powerful network functions. It has taken many security measures including controlling restrainedly reading and writing, the protection of the sub-system, audit trail and inner authorization and so on, which provides the user in multi-user network environment with the necessary safeguards.After analyzing the mail server and the architecture, I put forward to the designing scheme. According to the reliability, safety, management rules, I construct and configure mail system, integrate many kinds of mail safety configuration and optimize the Email server, then add some patches in it, finally I implement the Web mail functions, the administration and statistics rebuild.Spam can be regarded as the most controversial by-product that has been brought human by Internet. It has spread throughout the Internet overwhelming and occupies network bandwidth, causing mail server congestion, and further decreases the efficiency of the entire network. It has become a tool of hacking for siding with the bully of, seriously affecting the image of ISP services. Being aim at Spam, I put forward to safety rebuild. Using the rule to combine with content filters deal with Spam.Finally, I have concluded my shortcomings in this design and realization and endeavour to search the direction which can enhance and improve the management and statistical services of mail server and develop the well-log monitoring. Based on a combination with statistics and rules, the next work is that we will achieve self-management of email system and achieve a mimic that a system administrator can determine whether it is spam. This is also a development direction for email filtering. In addition, we will continuely develop anti-spam technology and strengthen the ability of anti-spam for email server. With the upgrade of the software and the increasing of the software tools, the upgrade of email server software will soon be on the agenda up to increase some new patches for security and reliability of the mail server, which is also very essential. |
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