Installing and configuring a mail server. Setting up email programs on your computer

You can work with emails not only through the Yandex.Mail web interface, but also using various email programs installed on your computer.

Configure the program using the IMAP protocol

When using the IMAP protocol, the mail program synchronizes with the server and maintains the folder structure of your mailbox. The letters sent by you through the mail program will be stored not only on the computer, but also on the server, and you will be able to access them from various devices.

Before configuring the mail program, enable the IMAP protocol:

To configure a mail program using the IMAP protocol, you must specify the following data:

Incoming mail

connection protection - SSL;

port - 993 .

Outgoing mail

connection protection - SSL;

port - 465 .

. en »

Support for the IMAP protocol will be enabled automatically upon first authorization in the mail program.

When using the POP3 protocol, all messages from the folders that you specify in the menu Setting → Email programs, will be saved by the mail program to your computer in the Inbox folder. If necessary, you can set up filters in your mail program to automatically move messages to desired folders. The emails you send will only be stored on your computer.

Note. When downloading emails from a server using the POP3 protocol, Yandex.Mail automatically saves copies of emails on the server, but you can delete emails manually using the web interface. If you want to delete emails with a mail program, use the IMAP protocol.

Before setting up the mail program, enable the POP3 protocol:

To configure a mail program using the POP3 protocol, you must specify the following data:

Incoming mail

connection protection - SSL;

port - 995 .

Outgoing mail

mail server address - smtp.yandex.ru;

connection protection - SSL;

port - 465 .

To access the mail server, enter your Yandex username and password (or if you have enabled two-factor authentication). If you are setting up receiving mail from a mailbox of the form " [email protected]en », the login is the part of the address before the "@" sign. If you use , you must specify as a login full address mailbox.

You can set up receiving emails via POP3 protocol from any folder, including Spam. To do this, open the menu Setting → Email programs and mark the desired folders.

When downloading the contents of the mailbox by mail programs, messages are not marked as read by default. If you want to mark received emails as read, enable the appropriate option.

Problems with the mail program

it step by step guide will help you solve problems related to Yandex.Mail and the mail program.

This step-by-step guide will help you solve problems related to Mail in Connect and your mail program.

Select an issue:

What message did you receive?

Did you manage to login?

So the problem was that you didn't accept the terms. They are accepted automatically when you log in to the Yandex.Mail web interface for the first time.

Make sure that the protocol you want to use is enabled in the settings section.

Please make sure that you have correctly\n specified the following server settings in your mail program settings:\n \n \n

If you are using IMAP

\n

mail server address - imap.yandex.ru;

\n

connection protection - SSL;

\n

port - 993 .

\n

\n

mail server address - smtp.yandex.ru;

\n

connection protection - SSL;

\n

port - 465 .

\n

\n \n \n \n\n

\n \n \n \n

If you are using POP3

\n \n \n Incoming mail \n \n

\n

mail server address - pop.yandex.ru;

\n

connection protection - SSL;

\n

port - 995 .

\n

\n \n \n \n Outgoing mail \n \n

\n

mail server address - smtp.yandex.ru;

\n

connection protection - SSL;

\n

port - 465 .

\n

\n \n \n \n\n

\n \n \n \n\n

For more information on how to check server settings in different mail\n programs, see the section.

\n ")]))">

Make sure that you have accurately specified the following server settings in the mail program settings:

If you are using IMAP

Incoming mail

mail server address - imap.yandex.ru;

connection protection - SSL;

port - 993 .

Outgoing mail

mail server address - smtp.yandex.ru;

connection protection - SSL;

port - 465 .

If you are using POP3

Incoming mail

mail server address - pop.yandex.ru;

connection protection - SSL;

port - 995 .

Outgoing mail

mail server address - smtp.yandex.ru;

connection protection - SSL;

port - 465 .

For more information on how to check the server settings in different email programs, see the Encryption of transmitted data section.

If the message "Authentication required" appears, "Sender address rejected: Access denied" or “Send auth command first”, authorization on the Yandex SMTP server is disabled in the mail program settings. Make sure the option is enabled User Authentication(for Outlook Express) or SMTP authentication(for The Bat!).

If you are a member of an organization and the problem is reproduced in all mailboxes of the domain, you need to log in to the web interface for each of them. It will not be possible to do this centrally, because each Mail user must accept the terms on their own.

If a message occurs "Sender address rejected: not owned by auth user", the address from which you are trying to send an email does not match the one under which you are authorized on the SMTP server. Make sure that in the settings of the mail program, the return address is exactly the address from which the login is used in the authorization settings for SMTP.

If you are a member of an organization and the problem is reproduced in all mailboxes of the domain, you need to log in to the web interface for each of them. It will not be possible to do this centrally, because each Mail user must accept the terms on their own.

If a message occurs "Login failure or POP3 disabled", the mail program cannot access the mailbox using the POP3 protocol. Make sure that you have entered the correct password for the mailbox and that access via the POP3 protocol is enabled in the settings section.

If you are a member of an organization and the problem is reproduced in all mailboxes of the domain, you need to log in to the web interface for each of them. It will not be possible to do this centrally, because each Mail user must accept the terms on their own.

If a message occurs "Message rejected under suspicion of SPAM", the content of your message was recognized by Yandex.Mail as spam. To solve the problem, open Yandex.Mail and send any one email as a test. This way you will prove to the system that the letters are not sent by a robot.

Check your computer for viruses with free antivirus programs: CureIt! from Dr.Web and Virus Removal Tool from Kaspersky Lab.

If you are using antivirus program, firewall or proxy server, disable them and see if this reproduces the problem.

If you are a member of an organization and the problem is reproduced in all mailboxes of the domain, you need to log in to the web interface for each of them. It will not be possible to do this centrally, because each Mail user must accept the terms on their own.

Read step by step instructions to search for missing letters. Before starting work .

Select an issue:

When you delete emails, they go to the Deleted Items folder and are kept there for 30 days. During this period, you can restore them:

Go to the Deleted folder.

Highlight the letters you want.

Click the Go To Folder button.

If more than a month has passed since they were deleted, you won't be able to restore the messages - they were permanently deleted from the Yandex.Mail servers.

If the letters are not in the folder where they should be, then most likely they ended up in another folder, for example, in Deleted or Spam. If you remember the name or address of the sender, part of the text of the letter or the subject - try to search for letters in all folders in your mailbox.

Did you find letters?

You can recover emails:

Navigate to the folder where the emails were found.

Highlight the letters you want.

Click the Go To Folder button.

Select the folder where you want to move the messages from the list - for example, Inbox.

Why Emails Disappear and How to Avoid It

In the Deleted mail folder, 30 days are stored, in the Spam folder - 10 days. After that, they will be permanently deleted from Yandex servers. Why emails can end up in these folders without your knowledge:

Another user has access to your mailbox

Emails can be deleted by a user who has access to your mailbox: you may have forgotten to log out after working on someone else's device. To end a session, click on the menu account link Sign out on all devices. You can also do this on the page - using the link Sign out on all computers.

Letters disappear in the mail program

configure the program using the POP3 protocol

Set up a rule that deletes or moves letters Letters disappear in the mail program

If you use a mail program and delete letters in it, then they disappear on . This happens because your program is configured using the IMAP protocol - while the structure of the mailbox on the service is synchronized with the structure of the mailbox in the program. To delete messages only in the program, but leave them in Yandex.Mail, you can configure the program using the POP3 protocol, but we recommend that you do not do this: letters may not be synchronized correctly with the server.

Set up a rule that deletes or moves emails Specify reliable ones in Yandex.Passport and link them to your account. Perhaps our security system found your account suspicious and blocked the mailbox. Most often this happens due to the fact that a phone number is not attached to the box or a fictitious name and surname are indicated in the Passport. It usually takes a couple of hours to unlock.

If you delete messages in a mail program, but they are still in their folders on the Yandex.Mail website, then most likely your mail program is configured using the POP3 protocol. Due to the peculiarities of the POP3 protocol, messages in the mail program may not be synchronized correctly with the server. It is recommended to use the IMAP protocol to work with Yandex.Mail. To migrate your email program from POP3 to IMAP, see Switching from POP3 .

If your email program doesn't show sent emails, then most likely your email program is configured with POP3 protocol. Due to the peculiarities of the POP3 protocol, messages in the mail program may not be synchronized correctly with the server. It is recommended to use the IMAP protocol to work with Yandex.Mail. To migrate your email program from POP3 to IMAP, see Switching from POP3 .

If you receive invalid certificate errors when activating SSL encryption in your mail program, make sure that your mail program and operating system configured correctly:

Add a certificate to the list of trusted certificates manually (Windows)

Attention. If you are not sure that you can install the certificate yourself, contact a specialist.

To add a certificate to the list of trusted certificates:

Download the certificate. (If the linked file opens directly in the browser, click CTRL + S and save the file to your computer; you don't need to copy the text from the file.)

Open the Start menu.

In the search box, type certmgr.msc and press the Enter key.

In the program window, in the folder tree, click on the folder Trusted Root Certification Authorities.

In the right part of the window, right-click on Certificates and select All tasks → Import.

Each mail client has its own interface for customization.

Some client programs require the introduction of all settings manually, while others receive settings automatically from the provider database.

Consider the basic steps that are performed when setting up any email client. This information can be used to settings for most email programs.

To use mail services, you need to register a mailbox on the website of the mail provider, enter your username and password to access the mail, the password must be remembered or written down. Your email address will look like - your-login@provider-site.

In this article, you will find configuration information for several popular mail providers.

To receive or send mail, authorization is required; for this, you should specify your login and password in the appropriate fields when setting up the client. You may also need to do this when setting up an incoming mail server and a server for sending messages, but most email clients remember the data you enter and use it automatically afterwards.

Let's define the terminology used in this article:
• SMTP - Simple Mail Transfer Protocol, literally - a simple mail transfer protocol. Allows you to send messages from the user's computer to the server and further along the chain of servers.
• POP3 - Post Office Protocol 3, literally - post office protocol. Contains commands for connecting to the server and downloading messages to the client computer.
• IMAP - Internet Message Access Protocol, a protocol for accessing e-mail. Provides access to emails stored on the server without downloading the contents of emails and attachments to local computer.
• Mail provider (ISP) - the email address of a site that provides a mail service, for example mail.ru. As a rule, incoming and outgoing mail servers are running on its subdomains.
• Incoming mail server - the email address of the server to which the mail client must connect to receive mail, for example pop.yandex.ru or imap.yandex.ru .
• Outgoing mail server - the email address of the server to which the mail client must connect to send mail, for example smtp.meta.ua .

Incoming mail setup:

To receive mail, two protocols are used - POP3 and IMAP, select the protocol you need, it is preferable to select IMAP if your mail provider supports it.
If the client program supports traffic encryption, set the SSL/TLS method for greater security.
Enter the incoming mail server address and port number, you will find the data required for this in the table below:

Provider	POP3 incoming mail server	POP3 Port No.		IMAP incoming mail server	IMAP Port No.
		Normal	SSL		Normal	SSL
rambler.ru	mail.rambler.ru	110	995	mail.rambler.ru	143	993
yandex.ru	pop.yandex.ru	110	995	imap.yandex.ru	143	993
gmail.com	pop.googlemail.com	110	995	imap.googlemail.com	143	993
bigmir.net	pop.googlemail.com	110	995	imap.googlemail.com	143	993
meta.ua	pop3.meta.ua	110	995	---	---	---
mail.ru	pop.mail.ru	110	995	imap.mail.ru	---	993

Outgoing mail settings:

The SMTP protocol is used to send mail, you just have to choose whether to encrypt the traffic or not. It is preferable to use SSL/TLS if the email client supports encryption.
To fill in the fields corresponding to the outgoing mail server address and port number, use the information in the table below:

Provider	Outgoing server SMTP mail	SMTP Port No.
		Normal	SSL
rambler.ru	mail.rambler.ru	587	465
yandex.ru	smtp.yandex.ru	25, 587	465
gmail.com	smtp.googlemail.com	25, 587	465
bigmir.net	smtp.googlemail.com	25, 587	465
meta.ua	smtp.meta.ua	25, 587	465
mail.ru	smtp.mail.ru	25, 587, 2525	465

Save the settings and test your email client.

• From:
• Registered: 2014.07.08
• Posts: 3,958
• Likes: 533

Topic: How to set up a mail server

Examples of how to set up an SMTP server for Gmail, Yahoo, Hotmail, AOL accounts

Instructions for setting up an SMTP server

Enter your email address in the Email address field.
Enter the name of the outgoing mail server in the Server field.
Specify a port.
Enter your account name in the User field.
Enter your password in the Password field.
Enable the SSL option if the server needs a secure connection.
Gmail SMTP account settings

Server: smtp.gmail.com
Port: 465
SSL: Option enabled
Note: Activate "POP Download" or "IMAP Access" option in your Gmail account (Go to "Settings" -> "Forwarding and POP/IMAP").

Yahoo SMTP account settings

Server: smtp.mail.yahoo.com
Port: 465
SSL: Option enabled
Note: Enable "Web & POP Access" in your Yahoo account (Go to "Options" -> "Pop & Forwarding")

Hotmail SMTP account settings

Server: smtp.live.com
Port: 587
SSL: Option enabled

AOL SMTP account settings

Server: smtp.aol.com
Port: 587
SSL: Option enabled

2 Reply by PunBB

• From: Moscow, Sovkhoznay 3, apt. 98
• Registered: 2014.07.08
• Posts: 3,958
• Likes: 533

Let's start with the oldest mail service Mail.ru. After completing a simple and understandable registration procedure, you will receive a mailbox in any of the four domains of your choice (mail.ru, inbox.ru, bk.ru, list.ru). The size of the mailbox is unlimited, initially equal to 10240 MB, as soon as your mailbox drops below 100 MB free space, the volume can be increased by another 2 GB.
The maximum size of the letter you send should not exceed 30 megabytes, the number of recipients of the letter should not exceed 30.
To configure a local email client using the POP3 protocol, use the following options:

Incoming mail server (Incoming message server POP3 server) - pop.mail.ru; port 110 (no encryption) or 995 (with SSL encryption)
Outgoing mail server (SMTP server) - smtp.mail.ru; port 25, 587 or 2525 (no encryption) and 465 (with SSL encryption)
The username (login) on the POP server and on the SMTP server is the full name of your mailbox, including the username, the "@" dog icon and the domain (for example, [email protected]);

To features this service It is worth mentioning the ability to use a non-standard SMTP port 2525 in the settings (in addition to the standard 25 and 587) to bypass the prohibition of some Internet providers outgoing TCP connections on port 25 and, alas, the complete lack of support for the IMAP protocol.

after sending 120 letters, there were significant delays in mail delivery (up to 40 minutes), after sending 182 letters, error 553 began to appear (the server does not want to send mail), which disappeared after a while (from 5 minutes to an hour) and arose again after sending letters. After 2 days, the restrictions continued to operate. The picture didn't change much even after sending responses to the initial mailing list (no more than 5 emails per hour). It is not advisable to use the free mail service Mail.ru, like any other free mail services, for any serious mailing.

3 Reply by PunBB

• From: Moscow, Sovkhoznay 3, apt. 98
• Registered: 2014.07.08
• Posts: 3,958
• Likes: 533

Re: How to set up a mail server

In the Russian segment of the Internet, perhaps one of the most popular free mail services is Yandex.Mail.
Immediately after registration, the volume of the mailbox is 10 gigabytes. As soon as less than 200 megabytes of free space remains in it, the mailbox will automatically increase by 1 gigabyte, provided that the user logs in regularly, enters the Yandex.Mail web interface using a browser.

It should be especially noted that for a newly created mailbox, you must first enable the use of the POP3 and (or) IMAP protocols in the Yandex.Mail web interface before you start working with this mailbox in your mail client. This feature, unfortunately, is a very common cause of failure to send and receive mail in an absolutely correctly configured mail client! Be careful!

So, here are the basic parameters for setting up a mail program using the POP3 protocol:

Incoming mail server (Incoming message server POP3 server) - pop.yandex.ru, port 110 (without encryption) or 995 (with SSL encryption)
Outgoing mail server (SMTP server) - smtp.yandex.ru; port 25 or 587 (no encryption) and 465 (with SSL encryption)
The username (login) on the POP server and on the SMTP server is, in this case, the first part of your email address before @yandex.ru, for example, if you have registered a mailbox [email protected], then "myname" should be specified as the username (without "@yandex.ru")
In the account settings, you must specify that the outgoing mail server (or SMTP server) requires authorization;
The basic settings for configuring an email program using the IMAP protocol are identical, with the exception of the incoming server:

Incoming mail server (IMAP server) - imap.yandex.ru, port 143 (without encryption) or 993 (with SSL encryption);
The maximum message size is 30 megabytes.

To the features of the service, you should add the so-called "one-time" addresses for your e-mail, which look like "your login + [email protected]", for example, [email protected] or [email protected] A message sent to such an address will be delivered to your inbox. This feature can be useful in many cases where you don't want to share your real email address.
Another feature is mail aliases (pseudonyms) of your mailbox in the domains @narod.ru, @ya.ru, @yandex.by, @yandex.com, @yandex.kz, @yandex.ua.

You can enable and configure this feature in your account settings on the Yandex.Mail web server. Subsequently, you will be able to receive letters to the aliases you configured. For example, you created an alias (alias) [email protected] and [email protected] Letters sent to these addresses will arrive in your inbox. More detailed information for these possibilities should be searched in the appropriate section help system Yandex.Mail.

The service also does not declare restrictions on the frequency of sending. During the experiments, it turned out that after sending 90 letters, an error 550 occurred, in fact, after that it was possible to send no more than 4 letters per hour. The delivery time of letters did not fall.
After 2 days, the restrictions also continued to operate. On the 3rd day after generation return letters the possible speed of delivery to new addresses exceeded 80 letters per hour and remained at this minimum for a day.

The parameters for setting up an email client using the POP3 protocol are as follows:

Incoming mail server (Incoming mail POP3 server) - mail.rambler.ru, port 110 (without encryption) or 995 (with SSL encryption);
Outgoing mail server (SMTP server) - mail.rambler.ru, port 25 or 587 (without encryption or STARTTLS encryption) and 465 (with SSL encryption);

The username (login) on the POP server and on the SMTP server is the full name of your mailbox, including the username, the "@" dog icon and the domain (for example, [email protected]);
In the account settings, you must specify that the outgoing mail server (or SMTP server) requires authorization;
The settings of the mail program using the IMAP protocol are identical, except for the incoming message server:

Incoming mail server (IMAP server) - mail.rambler.ru, port 143 (STARTTLS encryption) or 993 (SSL encryption);
Unencrypted IMAP connections are not allowed in this service. The configuration features include the requirement for the contents of the "From:" ("From:") field of the letter: the e-mail address you specified in the mail client settings must match the username that you use to log in to the SMTP server.

The size of files that can be attached to an email is limited to 20 megabytes.

The FossLook mail server is designed to create "internal" user mailboxes (on your domain) and work with them - receiving/sending messages. The server also initiates receiving messages from other mail servers (mail.ru, gmail.com, etc.), as well as sending them messages, if users registered on the server have external mailboxes. This article describes all the mail server settings

Creating and working with internal mail accounts is described. How to work with external mailboxes is described in the article.

To configure, run the Administration Wizard and go to the "Network" page:

it start page mail server settings. Consider all the settings dialogs that are launched when you click the appropriate links on the start page:

Channels

Channels is the most important page. After filling it out, you will be able to create and work with "internal" mailboxes using your own Domain name.

SMTP Settings section

• Option Use– enables or disables the possibility of exchange between the FossLook server and external mail servers.
• Port– port number for exchanging messages via the SMTP protocol.
• Certificate
• SSL Port

Section "POP3 settings"

• Use– enables or disables the ability to exchange between the FossLook server and external mail clients, except for MS Outlook.
• Port– port number for POP3 messaging.
• Certificate– certificate data for encrypted exchange.
• SSL Port– port number for encrypted exchange.

Section "Routing"

• Domain name– domain name of the machine on which the FossLook server is installed.
• FQDN– fully qualified domain name of the machine on which the server is installed.
• network interface– IP address network card server that connects to the Internet.
• Do not take more than– maximum limit on the size of an incoming message.
• frame relay– domain name or IP address of the intermediate server to which all correspondence will be sent, and from which it will be sent further to the recipients.

Section "Additional connection to the server"

• Use– enables or disables the external channel for working with the server via the Internet.
• network interface– IP address of the network card that is involved in establishing a connection to the Internet.
• Port– port number for connecting to the Internet.
• Machine name– external domain name (obtained from the provider).

To work with internal mailboxes (within your network), it is enough to fill in the required fields in the POP3, SMTP and Routing settings sections. In order to send letters from internal mailboxes to external ones (on servers on the Internet), you need to set up a channel to work with the server via the Internet.

General Internet Mail transport settings

The settings page of the Internet Mail transport module that maintains the mail server:

The purpose of the elements of this page is as follows:

• Option Included– enable/disable module operation (i.e. enable/disable mail server).
• Path to the service folder on the server– an alternative way to store logs and other service files of the mail server. If empty, the default path is used.
• Option Allow delegated message sending– this option is valid when the user has been delegated the authority of another user or department, and he sends messages on behalf of another user (department). When this option is enabled, the recipient's attributes of messages in the column "sender" indicate the real sender of the message, and in the column "on behalf of" - the user on whose behalf the message was sent. If the checkbox is cleared, both columns show only the user (department) on whose behalf the message was sent.
• Logging type SMTP, POP3– protocol logging type, you can choose: disable, logging to one file, logging to several files (each session is logged in separate file), you can also enable adding the message body to the logs.

The purpose of the elements of this page is as follows:

• Replacement address list– lists of replacement of message recipients of the form "address to which the letter is sent"; "address to which it arrives".
• List of Local Address Exceptions– a list of local addresses from which you can send letters without authorization.
• Time-out outgoing connection – connection timeout with other SMTP servers when sending mail.
• Maximum number of messages per session– the maximum possible number of messages that the server can receive via SMTP at one time. Messages can be received from both mail clients and other mail servers.
• Maximum message size, megabytes– maximum allowable message size for sending/receiving on the server, Mb.
• Option Allow deleting messages by POP3– allows deleting messages when receiving mail via POP3 from the mail server (another client).
• Interval for resending messages from the queue– sets the time (h:min:sec) after which the message will be resent from the queue (if the previous attempt failed).
• Number of resubmissions of messages from the queue– determines the number of resubmissions of messages from the queue (in case of unsuccessful previous submissions). If the message has not been sent after the specified number of attempts, it goes into the "Bad Messages" log.

The purpose of the elements of this page is as follows:

• Error recurrence period, minutes– if the error repeats within the specified time (in minutes), a notification is sent to the user.
• Mail check period– the period of checking external accounts for new messages.
• Option Receive only unread messages – enables receiving only unread messages from external servers.

, | |

When launching a website or web application, users typically set up a mail server to handle both incoming and outgoing mail. However, having your own mail server is often a serious vulnerability for a project for a variety of reasons. In general, setting up and maintaining a mail server is a complex and time-consuming task.

This guide covers many of the reasons that might keep you from using a mail server, as well as helping you find alternatives.

Mail Server Difficulties

A typical mail server consists of many software components, each of which performs a specific function. Each component must not only have fine tuning, but also interact with the rest of the components to provide the full functionality of the mail server. because of a large number"Moving" components of mail servers are quite difficult to install.

Components required for every web server:

• Message forwarding agent (mail transfer agent, MTA);
• Message delivery agent (mail delivery agent, MDA);
• IMAP and/or POP3 server.

• Spam filters;
• Antiviruses;
• Webmail (webmail).

Some software packages include functionality multiple components at once. In addition to software components, mail servers need a domain name that matches DNS records and an SSL certificate.

Let's consider the necessary components in more detail.

Message Forwarding Agent

The Message Transfer Agent (or MTA), which handles Simple Mail Transfer Protocol (SMTP) traffic, is responsible for:

• sending user messages to an external MTA (that is, to another mail server);
• receiving messages from an external MTA.

Examples of MTA programs: Postfix, Exim, Sendmail.

Message Delivery Agent

A message delivery agent (or MDA), sometimes referred to as a Local Delivery Agent (LDA), retrieves messages from the MTA and places them in the appropriate user's mailbox.

There are a huge variety of mailbox formats (eg mbox and Maildir). Each MDA supports a specific mailbox format. The mailbox format determines how messages are stored on the mail server, which in turn affects disk usage and mailbox access speed.

Examples of MDA programs: Postfix and Dovecot.

IMAP and/or POP3 servers

IMAP and POP3 are the protocols used by email clients, that is, any software to read and retrieve messages. Each protocol has its own complexities; this article explores some of their key differences.

IMAP is a more complex protocol that allows, among other things, to support multiple clients to connect to an individual mailbox at the same time. E-mail messages are copied to clients, while the original remains on the mail server.

The simpler POP3 protocol moves email messages to the mail client computer (typically the user's local computer by default).

Examples IMAP servers and POP3: Courier, Dovecot, Zimbra.

Spam filters

The purpose of a spam filter is to reduce the amount of incoming spam or junk mail, which gets into users' mailboxes. To achieve this goal, spam filters apply spam detection rules that take into account various factors (message sender, content, and more) to evaluate the message. If this score exceeds the so-called spam level, the message is recognized as spam.

Spam filters can also be applied to outgoing mail. This feature can be useful if mail account user has been hacked: this way you can reduce the amount of spam transmitted using this mail server.

Popular filter with open source code is .

Antivirus

Antiviruses are used to detect viruses, trojans, malware and other threats in incoming and outgoing mail. ClamAV is popular antivirus open source.

Webmail (or Webmail)

Many users need web mail. Web mail (in the context of working with a mail server) is a mail client that available to users through a web browser (Gmail is probably the most famous example). This component needs a web server (eg Nginx, Apache) and can be run directly on a mail server.

Examples: Roundcube and Citadel.

Mail server support

Now that you're familiar with the email server components that you need to install and configure, consider the following question: why can maintaining a mail server become too much of a chore and time consuming? There are routine maintenance tasks: updating antivirus and spam filter rules, keeping all components up to date, etc.; but there are many other things besides that.

Blacklists

One of the common problems with maintaining a mail server is the need to keep it out of blacklists (also called DNSBLs, blacklists, or blackhole lists). Such lists contain the IP addresses of mail servers that distribute spam or "junk" mail, as well as servers with incorrectly configured DNS records. Many mail servers subscribe to one or more of these blacklists and then filter incoming messages depending on whether the mail server that sent the message is on the list(s). If a mail server goes into an emergency, its outgoing messages will be filtered (and some blocked) before being sent to the recipient.

As a rule, a mail server that has fallen into an emergency can be excluded from this list. To do this, you need to find out the reason for blacklisting the server and eliminate it. Then you need to follow the process of removing the server from the lists and subscribe to at least one of them.

Troubleshooting

Although most people use email every day, not every one of them will be able to troubleshoot this complex system. For example, what if the sent messages were not accepted by the recipient? The problem may arise due to wrong setting one of the many components of the mail server (for example, due to a poorly configured spam filter for outgoing messages, or external factors such as blacklists).