Topic maintenance and control of the web server. Support, connection and maintenance of servers. Hardware support, server maintenance
If you have a small office and it is too expensive for you to buy Exchange and you don't have *nix- then this review is for you.
1) hMailServer
A fairly simple and convenient server. Has in the composition IMAP/POP3/SMTP server. There is a built-in spam protection system. For those who like to watch mail through Web- must be screwed separately Web-muzzle.
2) Mail Enable
I note that there are paid and free versions of this product. Has in the composition POP3/SMTP, but does not have IMAP server. But there is a built-in Web interface (which I never managed to get to work on IIS7)
3) Xmail
A fairly simple and functional mail server ( POP3/ESMTP, but no IMAP) with support for multiple authorization types ( PLAIN LOGIN CRAM-MD5 POP3-forward-SMTP and custom)
4) Office Mail Server
There is no official site, as the project is not developed. But you can download from here http://www.box.com/oms
A simple, compact yet fully featured LAN mail server with dial-up internet connection. Works under Windows 95-98-NT-ME-2000. Can work like NT service. A powerful sorter allows you to provide each user on the local network with a personal e-mail address. The program combines POP3 And SMTP servers, POP3 And SMTP clients, a sorter, a session scheduler, a dialer and a shell for setting up the server through the menu system and dialogs.
5) shicks!
Simple POP3/SMTP server written in python
6) Courier Mail Server
Almost similar to Courier Mail Server 1.56 (completely free) - however, there are minor flaws. For example, a glitch with displaying the interface when working with the server through a terminal session. However, this does not affect the work of mail. Its revised version 2.xx - www.courierms.ru Unfortunately, paid. Only up to 3 mailboxes work in it for free.
7) UserGate Mail Server
User Gate Mail Server is a solution for organizing secure email messages in a company with built-in anti-spam and anti-virus protection modules. The product has a modular structure, which increases fault tolerance and makes it possible to run the server on a distributed system.
Among the main functions User Gate Mail Server- domain and user management, web client, support for mailing lists, work with remote accounts, support LDAP, as well as a flexible and powerful system of rules. User Gate Mail Server capable of handling more 2000
letters per minute.
To provide access to mail in UserGate Mail Server implemented protocol support SSL, POP3s, SMTPs and IMAPs. Mail message security can now be ensured by three anti-virus modules at once: Kaspersky Antivirus, Panda Antivirus And Entensys Zero Hour based on cloud technologies.
In the processing of incoming messages in User Gate Mail Server filtering is performed in several stages - by connections, by source address, by destination address and by content. User Gate Mail Server supports the following spam filtering methods:
based DNS (DNSBL, RHSBL, Backscatter, MX, SPF, SURBL);
based on a distributed anti-spam system ("cloud" anti-spam);
based on statistics (own implementation of Bayesian filtering).
Besides User Gate Mail Server maintains control SMTP protocol (control of the correctness of commands in accordance with RFC), limits the maximum message size, the maximum number of recipients, etc.
The "cloud" antispam in the mail server filters messages based on the analysis of their content and heuristics.
IN User Gate Mail Server implemented integration with IMAP- server MS Exchange or Lotus Domino. Integration provides the ability to create a shared folder IMAP on a remote mail server and processing messages in these folders.
User Gate Mail Server provides information about all messages processed by the mail server. Message monitoring allows you to filter by date, by processing status (delivered/blocked), by source or destination address, push messages blocked as spam, and create exclusion lists.
Free license for 5 mailboxes
To get the opportunity to use UserGate Mail Server for 5 mailboxes for free, you need to:
Download distribution; In the registration window User Gate Mail Server select "Get a free version for 5 boxes".
The free mail server license does not include additional modules.
User Gate Mail Server supports backing up email messages, sending automatic replies, setting up mail processing rules, managing services in the web console, and selecting an arbitrary date range in the message history.
8) Rumble Mail Server
Rumble is a miniature mail server for personal use. The application can only be run from the command line interface of your system.
Features of the program "Rumble":
1. Support SMTP, POP3 and IMAP
2. Working with Apache
3. Easy to use
4. Rumble is free!
9) Humster
Hamster is a free server application for Windows that allows you to fully work with usenet news via the NNTP protocol and mail via the SMTP, POP3, IMAP protocols on the local network. Its feature is advanced message processing capabilities. It can independently collect mail from mailboxes on the Internet (similar to the operation of the fetchmail program in *nix), send it to a local mailbox after processing (similar to the operation of the procmail program in *nix), distribute via POP3, send via SMTP and NNTP. There is a setting of access rights to server resources for users. Rich macro language. SSL supported.
10) Axigen
Axigen mail server is a high class communication server integrating SMTP, POP3, IMAP and WebMail services. With very good configuration and security, it gives administrators excellent control over mail server traffic.
Selecting the tab Additional (Extended), you can change the various values for this account in the /etc/shadow file. On fig. 14.3 shows the appearance of the window User properties with tab Additional.
Rice. 14.3.
On fig. 14.3 you see several fields in the window User properties with tab Additional. Here, all password expiration dates are entered in the usual format, and there is no need for complex calculations involving the date January 1, 1970. If your system does not use shadow passwords, then these fields will not be available.
On fig. 14.4 shows the tab Groups window User properties. It displays all user groups available on the server. Here the mail system administrator can specify for the new user the belonging to one group or another.
Rice. 14.4.
And finally, in fig. 14.5 presents a window Edit defaults kuser programs. It gives the administrator the ability to set initial options for the account, just like the -D option for the useradd command.
Here you can set the shell and working directory for the new user, as well as prevent files from being copied from the /etc/skel directory to the working directory of new users, which is very convenient for the mail system administrator.
Rice. 14.5.
Mail server monitoring
It is the responsibility of the mail system administrator to monitor the operation of the e-mail server. Sometimes this turns out to be quite a tedious task. On the mail server, as a rule, several events occur simultaneously, and it is quite difficult to track them. First, you must constantly monitor your connection to the Internet to ensure that mail is properly circulating between your local email server and the Internet. In addition, here you can also observe attempts of unauthorized access to your server by hackers or attempts to use it by spammers. Secondly, special attention should be paid to the operation of the POP3 or IMAP services, through which users communicate with the mail server. As for user mailboxes, providing the necessary disk space for work is also included in the list of tasks performed by the administrator.
Thus, the mail system administrator must keep track of all these processes and respond quickly in case of any problems. Fortunately, Linux has several utilities that make life easier for the postal administrator. In this section, we'll look at Linux system reporting tools that can be used by an email system administrator to monitor the performance of a mail server and identify problems as they arise.
syslogd program
On the Linux operating system, the syslogd program keeps track of all events that occur on the system and logs them to the system's log files. As an administrator of an email system, you must be able to analyze the report files and use them to identify problems in the operation of certain services. Viewing and analyzing report files at least once a day should become a habit.
Typically, the syslogd program is started by the init process during system boot and runs in the background. In most versions of the Linux OS, it starts by default. You can check if it is running on your server using the command:
This command will display all the processes that are currently running on the system. When syslogd starts up, it reads its configuration file, which describes the types of messages that are placed in the log files and how they are generated.
System events that are subject to logging in report files can be specified by the mail system administrator. You can create as many report files as you need. Each of these files should contain information about certain system events or about the operation of only one of the system services. In table. 14.2 shows the types of system events that are found in Linux OS.
| Event | Description |
|---|---|
| auth | Events of authentication and security systems |
| authpriv | Private events of authentication and security systems |
| cron | cron daemon events |
| daemon | System Daemon Process Events |
| kern | Events related to the system kernel |
| lpr | Printer Events |
| Events in mail programs | |
| mark | Internal system resource integrity checks |
| news | News Reader Events |
| syslog | Internal events of the syslogd program |
| user | User level events |
| uucp | Events in the work of UUCP programs |
| local n | Local events (n takes values from 0 to 7 ) |
Each event has a priority, which is assigned in accordance with the importance of this or that event for the operation of the system. In table. 14.3 shows all kinds of priorities from the lowest ( debug ) to the highest ( emerg ). A lower event priority means events that are less important for system operation, and a higher priority means events that are critical for system operation.
| A priority | Description |
|---|---|
| debug | Events when debugging the system |
| info | Informational events (notifications) |
| Notice | Regular messages |
| warning | Warnings |
| err | Error messages |
| crit | Critical conditions for system operation |
| alert | Alarms |
| emerge | Fatal system errors |
In the following sections, we'll look at how syslogd works and how it can be configured to generate various log files.
One of the common and popular services is the administration of the email server. E-mail in our time remains the most popular and most frequently used means of exchanging information in electronic form. Active email correspondence inevitably accompanies the work on any project, documents are sent via email, business negotiations are conducted. The importance of email in today's world cannot be overestimated. This means that the tasks of ensuring its smooth operation are of particular importance. Of course, there are a significant number of free and fairly large e-mail systems on the World Wide Web, already maintained by high-level professionals. Such systems work stably and reliably, but their use in business correspondence is completely unacceptable for two reasons.
- It is not safe.
The situation when electronic messages, often of a confidential nature, are stored on a foreign server is too high a risk in terms of information security.
- The use of mailboxes registered in one of the free mail systems for business correspondence is simply undignified and absolutely does not fit with the image of a successful, modern company.
For many years I have been successfully engaged in technical support of client mail servers. And I can provide:
- constant monitoring of the technical condition of the mail server, the operation of its software; anti-virus check of incoming e-mail; application of a number of effective methods of protection against spam;
- backup of mail messages stored on the server;
- the ability to use a specialized web interface to work with mail.
The automated monitoring system used quickly and effectively captures all the failures in the operation of software and hardware, promptly notifying about them, which makes it possible to ensure stable and reliable operation of the administered server. And the applied data backup system prevents data loss in case of technical problems or accidental deletion by the client's employees.
All incoming and outgoing emails are automatically checked for the absence of malicious software and viruses, and anti-spam methods are also applied and constantly improved, based on a deep understanding of the functioning of the Network in general and email transmission protocols in particular.
For the convenience of clients, specialized web interfaces can be deployed for accessing personal electronic mailboxes and for administering the mail system: creating new mailboxes, managing disk resources available for each mailbox, etc. Working through the web interface is possible using any modern browser (web browser) and is carried out using a secure protocol, which guarantees the security of the connection. In addition, two-level mail systems were tested and implemented, consisting of an internal intranet system and an external mail server designed to work with electronic correspondence via the Internet. Such systems can significantly reduce the cost of external Internet traffic for the intra-office computer network, because. on the one hand, all spam is blocked at the level of an external mail server, and on the other hand, when using e-mail for internal correspondence of employees, their e-mails do not leave the local network.
By the way, the latter circumstance also makes it possible to further significantly increase the security of information exchange within the serviced organization.
Maintenance and control of the web server. Server configuration control. Restricting access to the server. Data transfer optimization
web server
web server A server that accepts HTTP requests from clients, usually web browsers, and provides them with HTTP responses, usually along with an HTML page, image, file, media stream, or other data.
A web server refers to both the software that performs the functions of a web server, and the computer itself on which this software runs.
The client, which is usually a web browser, sends requests to the web server for resources identified by URLs. Resources are HTML pages, images, files, media streams, or other data that the client needs. In response, the web server sends the requested data to the client. This exchange takes place over the HTTP protocol.
Additional functions
Web servers may have various additional features, such as:
automation of web pages;
Maintaining a log of user access to resources;
support for dynamically generated pages;
· HTTPS support for secure connections with clients.
Often, a mail server is also installed on a computer along with a web server.
Server log- files containing system information about the operation of the server, in which all user actions on the site are logged, as well as information used to analyze and evaluate sites and their visitors.
Authentication- an authentication procedure, for example, authenticating a user by comparing the password entered by him with the password stored in the user database.
HTTPS- extension of the HTTP protocol, to support encryption in order to improve security.
Server configuration
The server used to manage the main processes that occur on the local network requires a fairly large amount of power. The more server roles a management server has to perform, the more load it experiences. For this reason, it should not be surprising that server performance requirements are significantly different from those of a typical workplace.
The choice of server configuration can be carried out both at the stage of network design, which allows you to more accurately determine the cost of creating a network, and after the installation of the network is completed and the question of choosing a method for its functioning is being decided.
If the choice is made in the direction of using a domain structure, then the stage of choosing a server configuration will be mandatory, and buying a server is a must.
When choosing a control server configuration, the following features of its use should be taken into account:
uninterrupted work;
Providing authentication of network users;
· storage of all data about accounts of users and computers;
Can be used to perform additional roles, for example DNS(computer distributed system for obtaining information about domains) - and DHCP(a network protocol that allows computers to automatically obtain an IP address and other parameters necessary to work on a TCP / IP network) servers;
Possibility of application for service of web applications;
the possibility of using additional software, such as a corporate anti-virus system;
the ability to connect a data archiving system, such as a streamer;
Synchronization of time on all computers in the network.
In addition, an important issue is the choice of the server version: stand-alone installation or rack installation.
A separate installation implies the use of a stand-alone server, which over time leads to the fact that the server room is loaded with servers for various purposes. To keep order, you have to use makeshift furniture racks that allow you to install servers in two or three tiers.
Very often (especially for large networks) there are special server racks in the server room, which are used to install rack-mount servers for various purposes. In this case, as a rule, one keyboard with a monitor and a system of KVN switches are used to manage servers, which allows you to switch input systems and display systems to the desired server. This is quite convenient, since the front panels of the servers are always in front of your eyes, which allows you to visually monitor their performance, and the racks themselves have quite acceptable dimensions.
Even though a rack server takes up less space, it has a significant drawback compared to a stand-alone server - as a rule, only one power supply is used. A stand-alone server almost always has two power supplies, one of which is redundant, allowing you to keep the server running even if the main power supply fails.