Currently, there are a variety of Internet mail server products in the market, and these mail server products are different, and there are many different features. For network administrators, how to choose a full-service, reasonable email server product according to its own business, is a comprehensive decision-making issue of a multi-factor. When choosing a mail server, although there are many factors that need to be considered, it should focus on the system support capabilities, service agreement support capabilities, multi-mail server support capabilities, user management capabilities, mailbox management capabilities, client software support capabilities, communication Things of the following two factors such as capabilities, safety protection, system management capabilities, versions, prices, upgrades, and after-sales services. First, system support capabilities
Regardless of the computer products, the system's support capabilities are the first must consider, the hardware products are the same, the software products are the same. For mail servers, the following three issues should be examined in terms of system support capabilities:
1) Server running platform support capabilities
For a software server product, its support capabilities of its running platform are not unrestricted from single platforms and cross-platform. If a network administrator manages the network supports multiple operating systems, there are multiple separately managed mail servers, it is recommended to take priority cross-platform products when you must consider the convenience of collaboration and unified management of each mail server. Otherwise, you can only consider the product that satisfies your own platform.
2) Business processing power
Some mail server products are often divided into enterprise versions and standard versions, and the price of both products is very different. The former is mainly used for group users with a large number of users and many businesses to be treated, and the latter is used by small and medium-sized group users.
3) System processing power
The system processing capability of the mail server refers to its ability to perform information processing using the system hardware platform and software platform. Aiming at a server platform that supports multi-CPUs, some mail servers can be set to the number of client connections, each process allowed by each process, and the number of threads allowed for each process. 4) Load balancing support capability
In order to adapt to the needs of user traffic expansion, some mail server products now have a certain degree of multi-server load balancing support capabilities. In this mode of operation, the network administrator can add a mail server at any time according to the growth of business needs. After appropriate system configuration, multiple servers can share the mail service processing.
Second, the ability of service agreement support
The mail server is an Internet network service software product, which supports the Internet services for a variety of service agreements. When choosing a mail server product, check the ability to support the service agreement and is an important indicator for measuring product performance.
The network service agreement related to the mail server product has the following 6:
1) SMTP protocol
The SMTP protocol is an abbreviation for Simple Mail Transfer Protocol. This is the earliest, and is also the most basic Internet mail service agreement that is commonly used.
2) POP3 protocol
The POP protocol is an abbreviation of Post Office Protocol, which is a protocol that allows users to send and receive mail from the mail server. Combined with the SMTP protocol, POP3 is currently the most commonly used email service protocol.
3) IMAP4 protocol
The IMAP protocol is an abbreviation for Internet Message Access Protocol. It is now common to version 4, which provides users with a selection of selections that receive mail from the mail server, based on the server-based information processing and shared mailbox feature. IMAP4 is allowed to take a multi-segment processing method to query the message after the user logs in to the mail server. First, the user can only read the message header in the email address; then, the user can select the download specified message or all mail. IMAP4 keeps messages for users at one end of the mail server.
4) HTTP protocol and HTML language
The HTTP protocol is an abbreviation of Hyper Text Transfer Protocol, which supports the mail server for this protocol, which provides an email transceiver service through Web.
5) MIME protocol
MIME is an abbreviation for multi-purpose Internet Mail Extensions protocol. As the expansion of the SMTP protocol, MIME specifies the standards that transmit non-text email attachments via SMTP protocol. At present, MIME use has long been surpassing the scope of sending and receiving email, making it one of the basic protocols of multimedia information on the Internet.
6) LDAP protocol
The LDAP protocol is an abbreviation for lightweight directory access protocol. By storing the relevant content in a unified directory, the directory service provides users with information query means based on customer / server work. Third, multi-mail server support capabilities
Support multi-mail server has two meanings, physically supports multiple mail server collaborative work and logically supporting multiple virtual mail servers, also known as multi-domain mail services.
It is physically supported by multiple mail servers to work together, meaning that the product can build multi-level mail services in complex network environments. For a large mechanism, in addition to the enterprise-class mail server, each department is allowed to establish and manage sectoral-level mail servers themselves. Enterprise-level mail servers are directly connected to the Internet, and each department mail server is connected inside.
The so-called multi-domain mail service is through a physical server, providing an email service for institutions or departments of multiple independent registration Internet domain names. In the outside world, these institutions or departments seem to have a mail server with their own dedicated. So it is also known as a virtual mail server.
Fourth, other service support capabilities
1) Email paging service
The mail server that provides such a service can receive an email or simple content to the recipient's pager according to the request of the sender's email.
2) Mail to the fax machine service
Some mail servers also provide options, which can send mail received by the email to the fax machine specified by the email address according to the request of the sender.
3) Email User Group Service
The mail user group (MailingList) is also known as a mailing list, is a network service that communicates with special information information.
4) Network News Service
Network News is an invisible user exchange network that has a common hobbies on the Internet, in order to exchange opinions.
5) Multilingual services
Some mail servers also offer multi-language service support capabilities, allow administrators and users to enter custom text information for multiple languages, and automatically select the corresponding language based on the user's country feature.
V. User management capabilities
For system administrators who provide network services, user management is the most basic management. User management is first the management of user accounts. Usually a user account includes a series of properties, such as account names, account login passwords, user names, account establishment dates, account membership user groups, account email address, and so on.
Inspect the user account management feature of a mail server, you should first pay attention to the support capabilities of its user account type. The common user account type currently supported by the Mail Server includes a normal account, an alias account, a transfer account, an automatic letter reply account, an anonymous account, and a programmable robot account.
The ordinary account is the basic condition of the user to send and receive email, its account name is the Internet host domain name of the mail server, which constitutes the user's email address.
Due to business needs, users often need to use aliase accounts. An individual account is usually associated with one or more ordinary accounts. After the alias account receives an email, it will immediately forward it to the ordinary account associated with it.
When an account is set to a forwarding account (Forwarding Account), it automatically forwards the received email to the specified email address.
The email address of the AutoResponder is set to the AutoResponder, which can be replied to the content set in advance after receiving the letter.
An anonymous is required when you need to provide information query services through the public email. Anonymous accounts have no password. Anyone can read the letters of the mailbox.
The programmable robot account is currently new features provided by some mail servers. The "robot" here refers to a computer program that can be triggered by the email. When the e-mail address of the programmable robot account receives the letter, the program is immediately started, and the mail is automatically handled according to the function set by the program.
Taking the user account management feature of the mail server, you should also pay attention to the user account established method.
Hand-entered establishing a user account is the most basic method. In order to better combine with the operating system platform used, many mail servers now provide a method of directing or introducing an operating system user.
The user account information is saved, maintained, and the backup is convenient to be another side of the mail server user management capabilities. There are two main types of mail server user account information: Establish a private user database and use the operating system user database.
A functionally complete mail server product should provide a variety of means of providing user account management for administrators. Many mail server products now allow administrators to log in to user information in this unit, allow administrators to use web browsers to remotely log in to user management operations remotely via network remotely. Allows users to maintain personal account information from their own, and is an indispensable feature of mail servers. Six, mailbox management capabilities
When examining the mailbox management capabilities of the mail server, you should pay special attention to the storage method when the product is created by the user. There are currently three types: The first is centralized storage. The second is to establish a computer file subdirectory for each user mailbox. The third is to establish a computer file for each user email.
When inspecting the mailbox storage method, you should also pay attention to whether to support spanning physical disks. A system capable of accessing multiple physical disks in parallel can provide a higher user service response speed.
1) Single mailbox and multiple mailboxes
Since the mail service protocol used is different, the mail server is not the same as the mailbox or mailbox folder for each user.
2) Email capacity control
Many mail storage are provided for each user, and different mail servers provide different settings. The final hardware condition of the email capacity is the disk space that can be used.
3) Receiving mailbox management
How to manage users in user receiving mailboxes, different mail servers are different. For government agencies or businesses, email usually regards email as a body property, and does not allow employee's email system to send and receive private letters with business. Therefore, the agency hopes that the administrator of the mail server reserves the supervision of the user email. This does not involve the issue of personal privacy. But for institutions that provide public email services directly to individuals, you should pay attention to this problem.
4) Send a letter mailbox management
Sending a letter mailbox is also called a message queue. For letters waiting for the sent, the settingable feature that the mail server should provide includes the delivery interval, the retransmission interval, the retention time, and cannot be delivered to the letter processing. Whether to have a function of mail monitoring to the user, it is also one of the factors that choose the mail server to consider. Some mail servers can also choose whether to send a copy of the sent message to the location storage preferences specified by the administrator.
Seven, client software support capabilities
The client mail transceiver supported by the mail server is mainly related to the service protocol used by the server. Some SMTP / POP3 customers and IMAP customers are usually supported, and some also support web browser customers.
Eight, communication skills
When choosing a mail server, the investigation in communication is mainly involved in three aspects:
1) Connection mode support capabilities
To send and receive emails, the mail server is typically operated in mode that always maintains the connection with the Internet. If a local area network is a service line connection to the Internet Services Vendor ISP, the institution is a relay transferred by the Mail Server established by the local area network, then the mail server is required to call the phone dial-up communication support capability.
2) Access control capability
When the mail server provides a connection service for the user, the occupation of system resources is proportional to the number of communication connections. Some mail servers provide settings interfaces that can be controlled by parameters.
3) Communication bandwidth management capabilities
When the mail server is connected to the outside, it may take up a large number of communication channel bandwidth. In order to prevent the email server from excessive occupancy of bandwidth, some mail servers can set the maximum bandwidth occupied.
Nine, safety protection capabilities
The security protection capabilities of the mail server can be summarized as the following 13 aspects:
1) User authentication capabilities
2) Legal customer Website setting capacity
3) Resist spam ability
4) Email content filtering capacity
5) Resist commercial email forwarding capabilities
6) Support for mail service capabilities crossing firewalls
7) Support the ability of the proxy server
8) Support the ability of the fortress host
9) Support the ability to back up the mail server
10) The ability to detect and kill the mail virus
11) Resist the ability of "reject service" attack
12) Information Transmission Encryption Ability
13) Disaster recovery ability
Ten, system management capabilities
For the mail server administrator, the premise of system management is first for the full master of the system working, and then dynamic adjustments to the system running performance. Therefore, the product should provide at least three capabilities.
1) Audit
The Audit is the ability to operate the various services provided by the email server in accordance with the content selected by the administrator, and the needle formation system runs the audit history file for administrator analysis system. use.
2) Logging
Logs (log) is mainly for users to record for users using mail servers. The log feature provided by the mail server should allow the administrator to select log monitoring objects.
3) Real-time monitoring and performance adjustment capabilities
With real-time monitoring, administrators can perform real-time work in real-time work on various services that are running in the current mail server, dynamically adjust system control parameters. XI, version, upgrade and after-sales service capabilities
The mail server is a software system for multi-user service through the network. Developers are not only different from the business volume, but also the types of types of types, but also to release the upgraded version of the product with the advancement of network technology.
1) version
Different types of version of the mail server, mainly for different traffic applications. If you are classified according to the number of users support, you can divide a limited user version and an unlimited user version, and the former tends to be divided into several grades. If you are divided into standard version (Enterprise Edition), the former is often used in the standard version (Enterprise Edition), and the former is suitable for small and medium-sized mechanisms, which apply to large agencies or Internet service providers ISP, and may also have more support CPU processing capabilities. If you are classified according to the running system platform, it is often divided into UNIX system version and Windows NT system version. In addition, in order to sell its own products, various manufacturers often have a version of free trials. These versions are often set up internally. The operation is stopped over the trial period.
2) Upgrade support
When choosing a mail server, the manufacturer's upgrade support for the product is also a very important factor. Different types of versions of the same product are often different in terms of version numbers, features and upgrades. The number of mainstream product versions of users can often get a timely upgrade. Choosing such a product can continue to enjoy the new features provided by the developer.
3) After-sales service support
Since the mail server is a software technology product, the manufacturer's after-sales service support capacity is very important. When choosing a product, pay attention to whether it has a complete user manual and technical manual, manufacturers can provide any way and type after-sales technical service support. How to get an upgrade version when the product is upgraded.
Twelve, price
Price at all times is the factors that choose the product cannot be ignored. This involves cost accounting. Some mail servers have high prices, sometimes not just because of its functions. Products that support in a variety of system platforms are often higher than those running on a single system platform. In order to save unnecessary expenses, the product should be selected according to the actual needs of the business, and consider the standard price of the product, increase the price of the user's license and the product upgrade price.
