How to update a mail server on Windows. Choosing a mail server for medium-sized businesses: your own or a cloud one. Online course "DevOps practices and tools"

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. Contains IMAP/POP3/SMTP server. There is a built-in anti-spam system. For those who like to view mail through Web- needs to be screwed separately Web-muzzle.

2) Mail Enable

Please note that there are paid and free versions of this product. Contains 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 several types of authorization ( PLAIN LOGIN CRAM-MD5 POP3-before-SMTP and custom)

4) Office Mail Server

There is no official website because the project is not developing. But you can download it from here http://www.box.com/oms

A simple, compact, but fully functional mail server for a local network 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 email address. The program combines POP3 And SMTP servers, POP3 And SMTP clients, sorter, session scheduler, dialer and shell for configuring the server through a system of menus and dialogs.

5) chicks!

Simple POP3/SMTP server written in python

6) Courier Mail Server

Almost identical to Courier Mail Server 1.56 (completely free) - however, there are minor drawbacks. For example, a glitch with the display of the interface when working with the server through a terminal session. However, this does not affect the work of the post office. Its revised version 2.xx - www.courierms.ru Unfortunately, it is paid. It only works for free up to 3 mailboxes.

7) UserGate Mail Server

UserGate 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 a server on a distributed system.
Among the main functions UserGate Mail Server- domain and user management, web client, mailing list support, working with remote accounts, support LDAP, as well as a flexible and powerful rules system. UserGate Mail Server capable of processing more 2000 letters per minute.
To provide access to mail in UserGate Mail Server protocol support implemented SSL, POP3s, SMTPs and IMAPs. The security of an email message can now be ensured by three anti-virus modules at once: Kaspersky Antivirus, Panda Antivirus And Entensys Zero-Hour based on cloud technologies.
In processing incoming messages in UserGate Mail Server Filtering is performed in several stages - by connection, by source address, by destination address and by content. UserGate Mail Server supports the following spam filtering methods:
based DNS (DNSBL, RHSBL, Backscatter, MX, SPF, SURBL);
based on a distributed antispam system (“cloud” antispam);
based on statistics (own implementation of Bayesian filtering).
Besides UserGate Mail Server maintains control SMTP protocol (monitoring the correctness of commands in accordance with RFC), limits the maximum letter size, the maximum number of recipients, etc.
Cloud antispam in the mail server filters out messages based on analysis of their content and heuristics.
IN UserGate Mail Server 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.
UserGate 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, force messages blocked as spam, and create exclusion lists.
Free license for 5 mailboxes
To be able to use UserGate Mail Server for 5 mailboxes for free, you must:
Download distribution; In the registration window UserGate Mail Server select “Get free version for 5 boxes.”
The free mail server license does not include additional modules.
UserGate Mail Server supports backing up email messages, sending automatic replies, setting up mail processing rules, managing services in the web console, and selecting a custom date range in the message history.

8) Rumble Mail Server

Rumble is a miniature email server for personal use. The application can only be launched from your system's command line interface.

Features of the Rumble program:
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 a local network. Its feature is its advanced message processing capabilities. It can independently collect mail from mailboxes on the Internet (similar to the functioning of the fetchmail program in *nix), send it to a local mailbox, pre-processed (similar to the functioning of the procmail program in *nix), distribute via POP3, send via SMTP and NNTP. You can configure access rights to server resources for users. Rich macro language. SSL supported.

10) Axigen

Axigen mail server is a large-class communication server that integrates SMTP, POP3, IMAP and WebMail services. Having very good configuration and security, it gives administrators excellent control over mail server traffic.

Let's start with what I mean by medium-sized business. I don’t know the exact classification and I haven’t looked or checked anywhere. It intuitively seems to me that this is from 10-15 users to 200-300. I will consider the segment up to 100 users, since I work exclusively in this niche almost all the time. The problems and needs of larger companies are not reliably known to me. Although I’m not sure that anything will be fundamentally different from 100 people, I think the approaches will be the same, only the hardware will be more powerful. The problems of load distribution and clustering will most likely not arise here yet.

We have a small company of several dozen people. We need a mail server. Despite the fact that technology has long stepped forward, providing a lot of various means of communication, e-mail still firmly holds its position and is not going to give it up yet. At the same time, in such a small team, there are no great demands on the mail server. Most often, it is enough for the mail to simply work, without any special functional frills. Either an email client and the imap protocol, or a web interface will be sufficient. It would be good if it were possible to set up an auto-reply, create shared folders, a single address book, but you can live without it.

Among all the possible options for a mail service, I highlight 3 fundamentally different approaches to implementing the necessary functionality:

1. Services based on free email services from Google, Yandex or mail.
2. Your own mail server based on free software.
3. Exchange server from Microsoft.

Let's look at each of them in more detail.

Free mail from google, yandex and mail.ru

I'll make a couple of comments right away. I'm not sure that you can now register a free corporate email with Google. Everyone who registered earlier uses it for free, but only paid subscriptions are now available for new users. But this is not important and does not directly relate to the topic of the article. If Google has become completely paid for business, then we’ll simply exclude it from our list. Yandex and Mail.ru are still definitely free. I myself administered email domains in google apps and Yandex. I haven’t worked with biz.mail.ru, I just know that something similar is implemented there. Somehow I don’t like the company itself since the old days. Although now they seem to have turned to face the users, Amigo is still alive and well, so they have not completely turned around yet.

Let's look at the advantages of these mail services.

1. The most important advantage is that full-fledged mail is ready immediately after registration. There are no costs for purchasing hardware and setting up. It is enough for a more or less advanced user who, according to the instructions on the site, can connect a domain and create mailboxes. And you can already use mail.
2. Easy to administer and manage users, the web service provides all the necessary equipment for this. They are convenient and intuitive (though not always) understandable.
3. Comfortable and familiar web interface. Everything works quickly, from any place where there is Internet and a browser. There is a good mobile application.
4. Wide functionality, ready immediately after creating the box. Various filters, mail collectors, good antispam (from Google) and much more.

It seems like everything, I didn’t miss anything. It would seem that the advantages are obvious and significant. But before drawing conclusions, let's consider the disadvantages.

1. You do not manage this mail. She doesn't belong to you, is not on your servers. You don't know what's happening to her. If you have very sensitive and private correspondence, then suspicions and doubts arise about using popular email services. This may sound like paranoia, but this is a real concern for users and business owners and should not be discounted.
2. You are not immune from system failures and cannot prevent them in any way. And failures, although not often, do occur. Since the services are free, no one will guarantee you anything. And if some force majeure happens and the data is lost, they will simply say sorry to you. If you yourself do not have a very reliable IT structure, the likelihood of technical problems on your personal server may be higher. But you can control this and theoretically be able to build a system with a level of reliability that satisfies you.
3. Backup methods are not obvious and recovery of mailboxes in such services. There are situations when all letters are deleted from the mailbox. Let's say you can save them in various ways, simply by downloading them, but how can you return them back to the box, keeping all the dates original?
4. There is no way to analyze incomprehensible situations. For example, you send a letter, but it does not reach the recipient. What to do? In the case of cloud mail, you will not do anything, since you do not have any tools to analyze the situation. Just try sending a letter from another mailbox. Sometimes a letter doesn’t arrive to you, and you just can’t understand why it’s not there. But the issue may simply be an incorrectly configured filter. This is a common situation when there are a lot of filters, plus if some other forwarding is configured. Without access to server logs, it can be difficult to understand the situation. And if there is a mail server log, then it immediately becomes clear why the letter is not sent, or what happened to it after receiving it. You can know for sure whether the remote server received your letter or not.
5. There are no easy ways restrict access to mailboxes, for example, only from the office local network. Public service mailboxes are always accessible via the Internet. It is possible to solve this problem in google apps through authorization in third-party services. I have not seen the opportunity to implement such functionality in Yandex and mail.
6. We also need to understand that free cheese knows where it happens. It is not entirely clear how email services use the information received from users. Well, if only to show them relevant advertising. I think not only for this.

When I first started working about 10 years ago, there was no question about what email to use in the organization. Everyone set up their own mail servers and administrated them. At that time, free email services did not provide any email management tools for businesses. When such tools began to appear, I thought that soon no one would need their own mail servers, since they would no longer make sense. And all my torment (I don’t like working with them) with mail servers will become meaningless.

I was given the opportunity to administer domains based on public email services. After this, the above list of minuses appeared. And for me personally, these disadvantages outweighed the advantages, and now I still configure mail servers myself. Ultimately, it is more convenient and reliable when the pros and cons of use and administration are considered together.

The biggest disadvantage I see is the lack of full-fledged mail logs and a good backup scheme. It is inconvenient to analyze problems without logs. It is not possible to quickly and easily restore a deleted email to its original location, although this is a simple matter for open source mail servers.

Mail server based on free software

Let's look at the advantages and disadvantages of your own mail server based on free software. In principle, this includes some paid ones, for example Kerio Mail Server, which is also often used. I think it can be included here, since it provides similar functionality. I consider all mail servers collectively, without singling out individual representatives. Although in Linux, besides postfix and exim, I personally have not seen anything in production. I always use postfix myself, because I’m used to it and know it well. Let's take a closer look at the advantages of such servers.

1. You are in complete control of all information, which arrives by mail and is stored on your server. You can limit access to mail at your discretion using various technical means. You can centrally set up rules for deleting, for example, private information in letters, based on various criteria that you can set yourself.
2. The level of availability of the mail service depends only on you. With the right approach, you can provide the reliability that suits you system operation.
3. Flexible backup system. There are plenty of resources for organizing it, including free ones. It all depends on your needs, skills and capabilities. You can store various sections by date, by box, domain, or organize any suitable scheme.
4. Virtually unlimited functionality. Within reasonable limits, of course :) You can create mailboxes with only local correspondence, you can centrally manage the reception and sending of mail, and maintain your own white and black lists. You can set up various restrictions on mailboxes and domains. You can easily centrally manage duplication of mail for the required mailboxes, make all kinds of forwarding and much more.
5. All server monitoring tools are in your hands. You can deal with any unclear situation, having the mail server logs in hand. This service is well logged. I almost never had problems when it was not clear where the letter went missing. Most often, traces are found and one can definitely say what happened to the letter.

1. Necessary buy or rent equipment to organize your own mail server. In the case of a Linux server, the performance requirements will not be great. I usually have enough virtualization with 4 cores and 4 GB of RAM. The disk subsystem is much more important. Here, the faster the disks, the better. Don't forget about backup. It also requires iron resources.
2. Setting up a full-fledged, multifunctional mail server requires at least average knowledge of Linux system administration. That is, just admin username will not work here. Need a specialist with experience. He must have a decent salary. If such an admin is not on staff, I recommend hiring someone for one-time setup work. Most often, after setup, no special work is required to support the server if you do not change the functionality. It’s enough to simply monitor the free disk space and manage mailboxes via the web panel.
3. Ease of use via web interface will be lower than in free postal services. Whatever one may say, but the same gmail is implemented very conveniently. Quick search, filters, sorting, tags, etc. It's really convenient. I'm very used to it and can't use anything else.

These are the disadvantages of my email service that I see. The most important one for me is the last one. I myself am used to working with mail via the web. I don’t like to use email clients, although I have to. Web interfaces to free mail servers in terms of convenience and speed are far from being comparable to Gmail or Yandex; it makes no sense to compare. Nevertheless, I believe that for the average organization this is the most optimal option.

Pros and cons of Microsoft Exchange Server

I don't have much experience administering exchange. I tested it a long time ago when I was deciding which mail servers I would work with. I installed it and studied the functionality. Then I set up a mail server for the organization once. They wanted exchange. There were no problems, I quickly set it up using numerous guides on the Internet. The entry threshold for exchange mail server customizers is very low. Even Enike can handle basic functionality.

For medium-sized organizations, I think shared calendars are a really useful and difficult-to-replace functionality. And of course, the convenience of integration with AD, if available. And most often there is AD, since I can’t imagine administering a network for more than 20-30 people without Active Directory. I think that there is no point in saving here and you need to buy Microsoft Server.

Let's now look at the pros and cons of Microsoft Exchange Server. I warn you again just in case. I’m only telling you my vision, I have little experience working with the server, so I would like to receive comments on it myself in the comments in order to have a more adequate assessment of this system. Pros of Exchange:

1. Great functionality with relative ease of setup. Any administrator can deploy a server with basic functionality. Moreover, this basic functionality may be greater than that of any Linux build.
2. Active Directory Integration. You create a new user account and the mailbox is immediately ready for him. No special settings are needed if the user has Microsoft Outlook. A connection to the server is configured in a few clicks of the mouse.
3. Comfortable administration tools in the form of ready-made Windows Server snap-ins. Everything here is traditional for solutions from Microsoft.

The disadvantages of Exchange Server are as typical as the advantages for most products from Microsoft:

1. Price, price and price again. Microsoft Exchange Server is expensive. You need to count and figure out whether it will be justified to purchase it. To use all the built-in functionality, you will need to buy an edition of Microsoft Office with Outlook included for each workstation. These are additional costs.
2. For good performance it is required significantly more powerful iron, compared to Linux servers. And to support large mailboxes, for example 50 gigabytes, you will need very powerful hardware. Although such boxes for the same dovecot do not pose any special problems. In exchange, you will most likely use quotas to limit the maximum mailbox size.
3. For backup, you will most likely have to purchase decently powerful hardware and paid software. Here I’m just guessing, I really don’t know what is needed for a convenient exchange backup. I know paid software from popular vendors. Perhaps there is something free.

My conclusion about Exchange Server is that it is good in almost everything except the price. If it were free, I would most likely use it. For quite objective reasons, this is impossible. Good and convenient software does not appear on its own. You need to create it, and spend money on it, which you want to return with a profit.

Today, given the cost of Microsoft Exchange Server and Microsoft Office, I do not use these Microsoft products. Few people are willing to shell out the required amount for a mail server. I would like to take a closer look at Exchange in real conditions for at least 60-80 people in order to evaluate this server more objectively. But so far such an opportunity has not presented itself.

Conclusion

Let me summarize my thoughts about a mail server for a small, average organization. Although the conclusion, I think, is already clear. I myself prefer the second option I described - a mail server based on free software on Linux. But I wouldn’t discount the other two options. Free mail from public services will definitely be convenient for a very small team - 10-15 people. It makes no sense to fence your server for such a large number.

I would recommend using Exchange Server if you have it and don’t mind spending money on purchasing it. The product is definitely convenient, functional and easy to set up and administer. To put it simply, you need to understand that this is conditional. Configurations can be very complex, but in this case I am considering the entry level.

Online course "DevOps practices and tools"

If you have a desire to learn how to build and maintain highly available and reliable systems, learn continuous software delivery, monitoring and logging web applications, I recommend getting acquainted with online course “DevOps practices and tools” in OTUS. The course is not for beginners; to enroll you need basic knowledge of networks and installing Linux on a virtual machine. The training lasts 5 months, after which successful course graduates will be able to undergo interviews with partners. Test yourself on the entrance test and see the program for more details.

Date:2010-10-12

HmailServer - free mail server for Windows

hMailServer- free mail server for Windows. Supports IMAP4, POP3, SMTP, virtual domains, anti-spam, anti-virus and much more. Integrated ClamWin, SpamAssassin.

1) You need to download the latest version of hmailServer from http://www.hmailserver.com/index.php?page=download and start installation

2) We agree to the license agreement

3) Specify where hMailServer will be installed

4) Select the necessary components for installation

5) Select the SQL location method and the database itself.

6) Select and enter a password

7) Enter the password and connect to the mail server control panel

8) The control panel of your hMailServer server itself

Plutonit.ru - Administration, configuration of Linux and Windows 2009 - 2018

Installing and configuring Mail Server

Installing and configuring a mail server

Installing and configuring a mail server E-mail is a service that allows you to exchange electronic messages through a computer network. The main feature of email is that information is not sent directly to the recipient, but through an intermediate link - an electronic mailbox, which is a place on a server where the message is stored until requested by the recipient. A mail server is a computer program designed to organize the exchange of e-mail between computers. DIY mail server Its main functions are receiving letters from clients and delivering them to recipients. Clients can be both users (using an email client program) and other mail servers. Users, using a mail client program (Outlook Express, Thunderbird, etc.), can create letters, send them to the server and retrieve mail from their mailboxes on the server. Communication between the server and the client occurs using special mail protocols - Simple Mail Transfer Protocol (SMTP) - when sending letters to the server and Post Office Protocol v.3 (POP3) - when receiving letters from the mailbox. Clients connect to the server through certain ports. For SMTP the standard port is 25, for POP3 it is port 110. There are various mail servers. As an example, let's look at installing and configuring the Courier Mail Server. Courier Mail Server is a Windows mail server (email server) for local networks. It will help you quickly organize the exchange of e-mail on your local network and on the Internet. Courier Mail Server does not require installation on the system. It is enough to download the archive with the program and unpack it to any folder on the hard drive of the computer that will work as a mail server. You can download the free version of Courier Mail Server 1.56 from the website http://courierms.narod.ru/. A more functional Courier Mail Server 2.05, but already a paid version (1650 rubles for 10 mailboxes, the demo version is limited to only 3 mailboxes), can be found on the website http://www.courierms.ru/. In this example we will configure and use the free version of Courier Mail Server 1.56. Advantages of Courier Mail Server 1.56: free, easy to install and uninstall, compact, easy to administer, low consumption of system resources, multi-threading, convenient graphical shell, Russian-language interface and documentation, support for an unlimited number of mailboxes The program runs under Windows 9x/ME/NT/2000/XP. Setting up the program is quite simple and accessible to the average user. Note: in the example, all computers on the network are running Windows XP. All computers on the network are the same (there are no dedicated server computers). The teacher's computer is named kab39komp8, the students' computers are kab39komp1, kab39komp2, etc. All software discussed in this section is installed in the C:\MyServers\usr\local\ folder. If your computers have different names (and this is most likely the case 🙂), then take this into account when setting up the software. You can also select a friend folder to install the program. The CMS comes as a zip archive containing an executable file and documentation. To install the server, create a folder in which it will operate, extract the files from the archive into this folder and run the CourierMS.exe application. When the server is launched for the first time, it will automatically create the subfolders and files necessary for its operation inside its folder. The server does not make any changes outside its folder. The Windows registry changes only when registered as a service. Courier Mail Server can run as a standard application or as a Windows service. To run as a Windows service, start the CMS and in the Settings menu, select Start as a service. This will register the Courier Mail Server service in the system. If the startup occurs normally, the main server window will appear on the screen, and its icon will appear in the System Tray next to the clock. If messages about starting SMTP and POP3 servers appear in the main window and there are no error messages, you can start setting up the server. The next stage of setting up the mail server comes down to entering local domains. To do this, double-click on the word “domain” and a tab will open to configure it. Enter the name of the computer where the mail server will run. In our example this is kab39komp8. If your computer name is, for example, kab39komp5, then enter this name. Any server program involves entering users who will be served by it. Double click on "accounts" and the account editor will open. The account editor is designed to maintain a list of local users (accounts) of the server. When you create an account, a corresponding mailbox folder is also created. When you delete an account, the mailbox folder is automatically deleted along with all its contents. When you start the server for the first time, a postmaster account is automatically created. Create the required number of accounts for your users. It is enough to create one for each computer of the student and the teacher, although you can create a separate account for each student. Each account has the following settings: Real name: The name of the mailbox owner. Mailbox Name: The name of the mailbox. It is also the username when connecting to the server. Do not use Russian letters or special characters in the mailbox name, because... Some email programs do not work with them correctly. If the mailbox name is kab39komp2, the local domain is m, then the email address of this user is kab39komp2@ kab39komp8. Password: password for connecting to the server. We will not change other parameters. We create user accounts based on the number of users. You can restrict access to the mail server using an IP filter. Specify the range of IP addresses to which access is allowed. For us it is 192.168.1.1-192.168.1.11 (Read about IP addresses and their configuration in other articles in this section). At your school, this range may be different, for example, the one that was given to you by your Internet provider (well, that’s another article). All! The mail server can be used. You can read about setting up and using other features of the program in the help (in Russian!). You may ask: “how to use it? How to send and receive letters?” The answer is simple. We will send and receive letters using a program - an email client (Outlook Express, Thunderbird, etc.). Read about how to do this in the following article:

Setting up email clients for working with email

E-mail is a service that allows you to exchange electronic messages via a computer network.

You can work with email using mail program(mail client) installed on the user’s computer or using a browser using a web interface.

Mail program(e-mail client, mail client) - software installed on the user’s computer, designed to receive, write, send, store and process the user’s e-mail messages. Mail programs usually also provide the user with numerous additional functions for working with mail (selecting addresses from the address book, automatically sending messages to specified addresses, etc.).

The simplest email client is Microsoft Outlook Express.

It is included in the standard Windows package (starting with Windows 98) and therefore is available on every computer running this operating system. In Windows Vista it was replaced by the Windows Mail email client. The Bat! is also widely popular among users! and the free email client Mozilla Thunderbird.

In the last article, we looked at how to set up and run a mail server in our class. Now let's set up email clients and test the operation of our local mail.

In order for the mail client to be able to send and receive mail, in its settings you need to specify the addresses of the incoming and outgoing mail servers, as well as the account parameters for connecting to the mailbox (name and password).

Setting up email clients must be done on all computers of users who need access to email via a mail server.

How to raise a mail server

Service for initial installation and configuration of a mail server on your dedicated physical or virtual server

Setting up and configuring the mail server is carried out taking into account the wishes of the customer, and according to the intended purposes of use.

It is possible to install a mail server according to individual technical specifications, in accordance with specified requirements, options, and purposes of use. Or based on one of the ready-made, standard templates for using a mail server.

It is possible to deploy an email server on physical and virtual (vps, vds) servers running Linux OS (Debian, CentOS, Ubuntu), FreeBSD and also Windows.

As part of the server installation, the following mandatory settings are made, regardless of additional functions:

Deployment of a mail server can be performed on the basis of one or several (in combination) versions of licensed or open-source software for organizing a mail server.

Licensed software options:

• Microsoft Exchange Server;
• CommunigatePro;
• Kerio MailServer;
• MDaemon;
• Sendmail

Software options licensed under GPL (free software) for organizing a mail server:

• Sendmail (included in some Linux distributions);
• Postfix;
• Qmail;
• Exim;
• RoundCube;
• Afterlogic

It is possible to install email and collaboration software packages that are similar in capabilities to a licensed solution for corporate email - Microsoft Exchange Server.

Cost of installing and configuring a mail server

Based on one of the existing, popular usage patterns:

2,900 rubles5,900 rubles8,900 rublesFrom 18,900 rubles

A small mail server for private use, for a blog, website or small organization.

Software used:

From 1 to 10 mailboxes, 1 mail domain, 1 server IP address;
filtering of incoming mail (Greylist + SpamAssassin), web-interface for accessing mail.

The server can be installed according to this template or according to yours (technical specifications), which are similar in characteristics and complexity.

Installing and configuring a mail server for a small organization or a medium-sized web project, for example, according to one of the following popular usage patterns, implying an increased number of mail users, mailboxes and mail domains:

Software used: Exim / Postfix, RoundCube / Afterlogic;

From 1 to 30 mailboxes, up to 2 mail domains, filtering of incoming mail (Greylist + SpamAssassin), web interface for working with mail, web statistics of mail server operation

Installing and configuring a corporate mail server for a small, medium-sized organization or web project, for example, according to one of the following popular usage patterns, which involve independent management of mailboxes, domains, users, their limits and rights:

Software used:

These software solutions, by their characteristics, are an alternative to the licensed Microsoft Exchange Server product and provide full opportunity to independently configure, maintain and manage an unlimited number of mailboxes, mail users, their rights and domains.

The mail server is managed via a web interface. A complete corporate email system for a company.

Installation and configuration of a mail server according to the customer’s individual technical specifications.

Example of a possible installation template:

A cluster of two remote physical or virtual mail servers that duplicate or complement each other’s capabilities.

Software used: Exim / Postfix, RoundCube / Afterlogic, etc.

Any required number of mailboxes, users and domains. Independent management of the mail server via the web interface. Working with incoming and outgoing mail from an email program or through a web interface.

To order and discuss setting up a mail server, please contact us from the “Contacts” section.

How to create your own mail server?

Kerio develops functional solutions for small and medium-sized businesses.
Kerio MailServer 6 belongs to a new generation of mail servers for corporate networks. The advantage of Kerio MailServer is that it is cross-platform - it can work in Windows, Linux, Mac OS, and FreeBSD operating environments.

When working on Windows, you can use Microsoft Outlook as an email client, and on Mac OS, you can use Microsoft Entourage. In all systems you can use the Kerio WebMail web interface. There is also a version of Kerio WebMail Mini designed for installation on pocket computers. Kerio WebMail Mini supports Palm OS, Pocket PC and BlackBerry systems. Email clients Kerio WebMail and Kerio WebMail Mini are especially convenient for frequently traveling employees, as they allow you to work with mail on a corporate web server from anywhere. The second advantage of Kerio MailServer is the presence of a built-in antivirus and antispam module. For a mail server, such functionality is currently mandatory, and the integration of these functions within one product made it possible to achieve stability in operation and no need to integrate software from different manufacturers.

Mail

Kerio MailServer allows you to receive mail in several ways: via POP3 protocols (with the ability to SSL encoding), IMAP4 (with the ability to SSL encoding), using the WebMail graphical network interface (with the ability to SSL encoding), using smartphones and PDAs, wireless connection using BlackBerry, as well as using email clients Microsoft Outlook 2000/XP/2003 for Windows or Microsoft Entourage X/2004 for Mac OS X. To work with groupware when using Microsoft Outlook, you must install Kerio Outlook Connector, which is a programming interface email applications (MAPI provider), replacing the Microsoft Outlook MAPI Provider.

When you replace Microsoft Exchange with Kerio MailServer, you retain access to shared calendar events, shared contacts, and tasks found in Microsoft Outlook, Microsoft Entourage, and Kerio WebMail. Users can migrate to Kerio MailServer while retaining all group features such as calendar events.

To automate the migration from Microsoft Exchange Server to Kerio MailServer, the Kerio Exchange Migration Tool function is designed, with which you can transfer data from the following Exchange series servers: Microsoft Exchange Server 5.5, Microsoft Exchange Server 2000, Microsoft Exchange Server 2003. This function imports data blocks “ Users”, “Email”, “Contacts”, “Calendar Events”, “Tasks” to the corresponding directories of the Kerio MailServer mail server.

Safety

The security system includes the ability to use cryptographic traffic protection using SSL, an anti-spam filter, an anti-virus filter and an attachment filter. All filters are managed in one section, “Attachment Filters,” which simplifies and speeds up the administrator’s work.

Kerio MailServer has two-level virus protection: you can simultaneously use the integrated McAfee antivirus and a plug-in external antivirus package. In the event of a failure updating the databases or extending the license of one antivirus, the likelihood of infection is significantly reduced due to the work of the second. The list of supported plug-in antivirus programs includes AVG Antivirus 7 ESE (Grisoft), NOD32 Antivirus (Eset Software), eTrust Antivirus (Computer Associates), SAVI Antivirus (Sophos), Avast Antivirus (ALWIL Software), VisNetic/Kaspersky Antivirus (Deerfield), Symantec AntiVirus Scan Engine (Symantec). It is possible to use other antivirus programs. During virus epidemics, it will be useful that the built-in McAfee antivirus also scans internal corporate mail, which will slow down the spread of viruses internally among employees.

Kerio MailServer uses several methods to protect against spam. Supports SMTP authorization using IP address, real-time blacklists, content filtering, sender domain verification, Microsoft Caller ID. SPF identification is also supported. In addition, the software allows you to introduce restrictions on the number of parallel connections and limit the number of letters per unit of time sent from one address. Kerio MailServer implements technology to combat DHA attacks by slowing down responses, interrupting connections, and sending false responses. To enhance security, the product includes tools for backing up all incoming and outgoing email, address books, calendars and other collaboration items, as well as tools for limiting mailbox volume, attachment size and the number of messages in general.

Administration

To install Kerio MailServer, a server platform is not required. The Kerio MailServer mail server can be used both as an internal network server and as an Internet email server. The product has two administration interfaces - Kerio Administration Console and Kerio Web Administration. The Kerio Administration Console allows you to manage multiple mail servers and other Kerio Technologies products from one workstation, and remote access is provided via an encrypted channel. This is a standalone program that can be installed on any supported operating system. The administrator can also delegate authority to users to manage accounts using Kerio Web Administration. User data in Kerio MailServer 6.x can be managed using the internal database or directory services Microsoft Active Directory or Apple Open Directory.

Many system administrators experience certain difficulties when working with email systems. This is not surprising; a mail server has a much more complex structure than a file server, router or terminal server. In this article we will look at the structure and operating principle of mail servers, without understanding which setting up an email system can easily turn into shamanic dances with a tambourine.

This material contains quite a lot of simplifications and generalizations in order to give system administrators the necessary minimum knowledge. In our opinion, in order to administer one or two entry-level mail servers, it is not at all necessary to become an e-mail specialist.

For most users and novice administrators, a mail server is a kind of “black box” that, having received a letter through “unknown” ways, delivers it to the recipient and vice versa. All interaction with such a server consists of the mail client accessing certain ports, or even through the web interface. However, there is a whole mechanism hidden inside, understanding the operation of which is key to successfully setting up and maintaining an email system. This is especially important for administering servers on the Linux platform. Unlike Windows, where the mail server is a complete software solution and the developers have already taken care of internal interaction, in Linux the components of the mail server are separate programs and you need to configure their interaction yourself.

Let's look at the structure of the mail server, as well as what happens when a user tries to send mail.

The most important part of the mail server is MTA (Mail Transfer Agent-- mail forwarding agent) whose tasks include receiving and transmitting mail. Very often (in Linux / UNIX) the MTA is also called a mail server. MTA operates using the SMTP protocol, and it alone is, in principle, sufficient to create an email system. Once upon a time, this was exactly the case, and to access your mailbox you needed to have certain technical knowledge.

However, progress does not stand still; the MTA, upon receiving a letter, places it in the user's mailbox on the server, which the latter must access, preferably in the simplest and most understandable way. This is where it comes into play MDA (Mail Delivery Agent-- mail delivery agent), its task, at the request of an email client, is to transfer mail from a mailbox on the server to it. MDA can operate using the POP3 or IMAP protocols; in some cases, proprietary protocols with advanced functionality, such as MAPI (Exchange Server), can be used to “communicate” between the mail client and the delivery agent.

Contrary to popular belief, MDA has nothing to do with the mail transfer process. That's the MTA's prerogative. To make an analogy, the MTA can be thought of as the post office, which receives and sends mail, and the MDA is the postman, who brings the mail to your home. If the postman gets sick, this will not affect the work of the post office in any way, you just won’t receive letters at home. Also MDA, its failure does not lead to the inoperability of the mail server, only receiving mail by the mail client becomes unavailable, at the same time it can be easily accessed in other ways, for example, through the web interface.

Let's see what happens when sending mail. In our example, the user Ivanov, located in the example.org domain ( [email protected]), writes a letter to Kozlov in the example.com domain ( [email protected]). For Ivanov, the process of sending mail consists of creating a message and clicking the "Send" button in the email client. The mail client connects to the MTA using the SMTP protocol and first provides its credentials. After authorizing the user, the MTA accepts the message and tries to deliver it further.

In fact, authorization is not a mandatory procedure for MTA, but without authorization we will get an open relay, i.e. Anyone can use our server to forward mail, and how spammers will rejoice! Currently, open relays occur mainly due to server configuration errors. However, it is entirely possible for an MTA to accept mail from trusted users without authorization, for example from an enterprise’s local network.

For authorization, the MTA can use its own user list, system list, LDAP or AD user lists. There is also a way: POP authorization before SMTP, when the user authorizes the MDA before sending mail, which in turn confirms the user's authentication to the MTA.

The next step is that the MTA analyzes the service information of the letter, determining the recipient's domain, if it belongs to the domains served by this MTA, the recipient is searched and the letter is placed in his mailbox. This would have happened if Ivanov had written a letter to Petrov or Sidorov.

If the recipient's domain is not served by an MTA, a DNS query is generated asking for MX records for that domain. An MX record is a special type of DNS record that contains the names of the mail servers that process incoming mail for a given domain. There can be several MX records; in this case, the MTA tries to establish a connection sequentially, starting with the server with the highest priority. If there is no MX record, the A record (the address record that maps a domain name to an IP address) is queried and an attempt is made to deliver mail to the host specified there. If it is impossible to send a message, it is returned to the sender (placed in the user's mailbox) with an error message.

We will not consider the work of the receiving server, we will assume that everything went fine, Kozlov received a letter from Ivanov and wrote him a response. The server serving the example.com domain performs exactly the same actions and tries to transfer mail to our server. Having received an incoming message, the MTA, as in the case of a local sender, checks the recipient's domain, if it is among those served by the MTA, processing of the message continues, otherwise the server refuses to accept mail. After checking the domain, the recipient is checked, if he is present in the list of users, the message is delivered to his mailbox, otherwise two options are possible: refusing to receive the message or receiving the message in the general mailbox (administrator's mailbox). On the one hand, this setting increases the number of spam received, on the other hand, it allows you to avoid losing letters with misspelled addresses.

Another anti-spam measure is to request a PTR record. A PTR record (pointer record) associates an IP address with a domain name. By requesting PTR, the MTA only accepts mail if the sender's domain matches the domain of the sending server.

Let's look at the example in more detail. A certain spam server spam.com is trying to send letters with a fake sender, supposedly from the example.com server we know. If filtered by white/black lists, such a letter will be delivered, since the sender is a user from a trusted domain (which is what spammers were counting on). In order to combat spam, the MTA generates a PTR record request for the IP address of the sending server, which it reports during the SMTP session. For the address y.y.y.y, the PTR request will return the spam.com domain name, which does not match the sender’s domain, which will cause the message to be rejected. At the same time, messages from the server x.x.x.x will be received, since the domain from the PTR record for x.x.x.x (example.com) matches the sender's domain.

So, the message has been received and is in the user's mailbox. How to read it? Mail storage, where user mailboxes are located, can be organized in a variety of ways: from banal folders and files to a database. Without technical knowledge, it is unlikely that you will be able to read your own mail. But should user Ivanov really care about this? For him, the process of receiving mail is reduced to clicking the "Receive" button in the mail client.

To receive mail, the client establishes a connection to the MDA using the POP3 or IMAP protocol, always passing authorization data. MDA checks the presence of the user in the lists and, if the check is successful, transfers to the client all new messages in his mailbox. User Ivanov receives his correspondence and can work with it in a way convenient for him.

This is where our article ends; we strongly recommend thoughtful reading and assimilation of the material presented in it. Subsequently, when considering practical implementations of mail servers, we will present the material on the assumption that the reader has knowledge of at least this article.