Pop3 and smtp Internet services. Email ports. POP3 protocol and its ports

You can work with letters 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 protocol IMAP mail the program synchronizes with the server and saves the folder structure of your mailbox. The letters you send through the mail program will be stored not only on your computer, but also on the server, and you will be able to access them from various devices.

Before setting up mail program enable the IMAP protocol:

To configure an email program using the IMAP protocol, you must specify the following information:

Incoming mail

• connection security - SSL;
• port - 993.

• connection security - SSL;
• port - 465.

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IMAP protocol support will be enabled automatically the first time you log in to your email program.

When using the POP3 protocol, all letters from the folders that you specify in the menu Settings → Mail programs, will be saved by the email program to your computer in the Inbox folder. If necessary, you can set up filters in your email program to automatically move emails to required folders. 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 using an email program, use the IMAP protocol.

Before setting up your email program, enable the POP3 protocol:

To configure an email program using the POP3 protocol, you must specify the following information:

Incoming mail

• connection security - SSL;
• port - 995.

• address mail server- smtp.yandex.ru;
• connection security - SSL;
• port - 465.

To access the mail server, enter your Yandex username and password (or if you included two-factor authentication) . If you set up receiving mail from a mailbox like “login@yandex. ru », the login is the part of the address before the “@” sign. If you use, you must specify the full mailbox address as your login.

You can configure to receive emails via POP3 from any folder, including Spam. To do this, open the menu Settings → Mail programs and mark the required folders.

When mailbox contents are downloaded by email programs, emails 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

This step by step guide will help you solve problems related to your email program.

Select an issue:

What message did you receive?

If a message appears about no connection to the server, try logging into Yandex.Mail with the same username and password that you use in the program. Enter your username and password manually, without using those stored in the browser.

Make sure that in the Mail programs settings section, the protocol\n you want to use is enabled.\n

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

If you are using IMAP

\\n
• mail server address - imap.yandex.ru;
\\n
• connection security - SSL;
\\n
• port - 993.
\\n

\\n
• mail server address - smtp.yandex.ru;
\\n
• connection security - SSL;
\\n
• port - 465.
\\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 security - SSL;
\\n
• port - 995.
\\n

\\n
• mail server address - smtp.yandex.ru;
\\n
• connection security - SSL;
\\n
• port - 465.
\\n

\\n \\n \\n \\n\\n

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

\\n ")]))\">

Make sure that in your mail program settings you have accurately specified\nthe following server parameters:

If you are using IMAP

\n
• mail server address - imap.yandex.ru;
\n
• connection security - SSL;
\n
• port - 993.
\n

\n
• mail server address - smtp.yandex.ru;
\n
• connection security - SSL;
\n
• port - 465.
\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 security - SSL;
\n
• port - 995.
\n

\n
• mail server address - smtp.yandex.ru;
\n
• connection security - SSL;
\n
• port - 465.
\n

\n \n \n \n\n

Encryption of transmitted data.

\n\n ")]))">

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

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

If you are using IMAP

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

\n
• mail server address - imap.yandex.ru;
\n
• connection security - SSL;
\n
• port - 993.
\n

\n
• mail server address - smtp.yandex.ru;
\n
• connection security - SSL;
\n
• port - 465.
\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 security - SSL;
\n
• port - 995.
\n

\n
• mail server address - smtp.yandex.ru;
\n
• connection security - SSL;
\n
• port - 465.
\n

\n \n \n \n\n

For more information on how to check server settings in different mail programs, see the section Encrypting transmitted data.

\n ")]))">

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

If you are using IMAP

Incoming mail

• mail server address - imap.yandex.ru;
• connection security - SSL;
• port - 993.

• mail server address - smtp.yandex.ru;
• connection security - SSL;
• port - 465.

If you are using POP3

Incoming mail

• mail server address - pop.yandex.ru;
• connection security - SSL;
• port - 995.

• mail server address - smtp.yandex.ru;
• connection security - SSL;
• port - 465.

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

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

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

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

If your mail program does not accept or send letters, check that your mail program settings are correct, as well as your computer’s Internet connection settings.

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

Read step by step instructions to search for missing letters. Before you start.

Select an issue:

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

Go to the Deleted Items folder.

Select the required letters.

Click the To Folder button.

If more than a month has passed since they were deleted, it will not be possible to restore the letters - they have been 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 Deleted Items or Spam. If you remember the sender's name or address, part of the text of the letter or the subject, try searching for letters in all folders of your mailbox.

Have you found the letters?

You can restore letters:

Go to the folder in which the letters were found.

Select the required letters.

Click the To Folder button.

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

Why emails disappear and how to avoid it

The Deleted emails folder is stored for 30 days, and the Spam folder for 10 days. After this, they will be permanently deleted from Yandex servers. Why emails may 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: perhaps you forgot to end your session after working on someone else's device. To end your session, click on the menu account link Log out on all devices. This can also be done on the page - using the link Log out on all computers.

Letters disappear in the mail program

configure the program using the POP3 protocol

A rule has been configured that deletes or moves letters. Letters disappear in the mail program.

If you use a mail program and delete letters in it, they disappear on . This happens because your program is configured using the IMAP protocol - in this case, the mailbox structure on the service is synchronized with the mailbox structure 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 not doing this: the messages may not synchronize correctly with the server.

A rule has been configured that deletes or moves emails Indicate reliable ones in Yandex.Passport and link them to your account. Our security system may have found your account suspicious and blocked your mailbox. Most often, this happens due to the fact that the phone number is not attached to the box or the Passport contains a fictitious first and last name. It usually takes a couple of hours to remove the lock.

If you delete letters in your 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 synchronize correctly with the server. To work with Yandex.Mail, it is recommended to use IMAP protocol. To learn how to migrate your email program from POP3 to IMAP, see Migration from POP3.

If your email program does not display sent emails, then most likely your email program is configured using the POP3 protocol. Due to the peculiarities of the POP3 protocol, messages in the mail program may not synchronize correctly with the server. To work with Yandex.Mail, it is recommended to use the IMAP protocol. To learn how to migrate your email program from POP3 to IMAP, see Migration from POP3.

The report always indicates the reason for non-delivery. About the most common reasons can be read in the article web/letter/create.html#troubleshooting__received-report.

If you receive errors about an incorrect certificate when activating SSL encryption in your email program, make sure that your email program and operating system configured correctly:

• On a computer (without lags and "date from the future"). If the wrong date is set, the system erroneously determines that the certificate has not yet expired or has already expired.
• All installed.
• Checking HTTPS connections is disabled in your antivirus settings. You can change your antivirus settings according to our instructions for Kaspersky Internet Security and ESET NOD32 Smart Security See the Security Certificate Errors section.

Manually add a certificate to the list of trusted certificates (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 your browser, click CTRL + S and save the file to your computer; there is no need to copy text from the file.)

Open the Start menu.

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

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.

Click the Browse button and select the CA.pem file you downloaded earlier. Click Next.

SMTP, ODMR and MSA ports

Incoming SMTP port

MDaemon will monitor these TCP ports to detect incoming connections from SMTP clients. This is the primary SMTP port and should be set to port 25 by default in most cases.

Outgoing SMTP port

This port will be used to send mail to another SMTP server.

Incoming MSA port

This is an MSA (Message Submission Agent) protocol port that can be used by your users as an alternativeIncoming SMTP port, given above. Communication on this port requires the AUTH procedure, so users sending messages to this port must configure their email programs accordingly so that their connections are authorized. Also, since many ISPs block port 25, your remote users can bypass this limitation by using a fallback MSA port instead. If you do not want to assign an MSA port, set this field to “0” to disable it.

Incoming ODMR port

On this port MDaemon will listen for incoming ODMR (On-Demand Mail Relay) connections such as ATRN -requests from domain gateways.

SMTP SSL port

This specifies the port intended for mail sessions via the SMTP protocol using an encrypted SSL connection (Secure Sockets Layer). Cm. additional information in the SSL and certificates section.

POP and IMAP ports

Incoming POP port

MDaemon will listen on this port for incoming connections from remote POP clients.

Outgoing POP port

This port will be used when MDaemon receives mail from POP servers.

Incoming IMAP port

MDaemon will listen on this port for incoming IMAP requests.

POP SSL port

This indicates the port allocated for mail POP clients using an encrypted SSL connection (Secure Sockets Layer). See SSL and Certificates for more information.

IMAP SSL port

This specifies the port allocated for IMAP email clients using an encrypted SSL (Secure Sockets Layer) connection. See SSL and Certificates for more information.

Other ports

Outgoing DNS port

Specify here the port that MDaemon will use to exchange datagrams with the DNS server.

LDAP port

MDaemon will use this port to send database and address book information to your LDAP server.

Remote Admin Port

MDaemon will monitor this port to detect connections via Remote Administration.

Port Minger

This is the port on which the Minger server will listen for connections.

Restore port settings to default

Clicking this button will return all port settings to default values.

Bind to new port numbers now

If you have changed the values ​​of any of the port parameters, you should click this button for your changes to take effect immediately. Otherwise, the changes will take effect only after the server is restarted.

Chances are that most people reading this guide are already familiar with the most commonly used communication technology: email. But have you ever thought about how it actually works? In this article, we will learn how this service works and what POP3, SMTP and IMAP are.

POP3(protocol post office version 3) is often used to communicate with a remote server email and downloading messages to a local mail client and then deleting it on the server, for example, Thunderbird, Windows Mail, etc. However, email clients usually offer a choice whether or not to leave copies of messages on the server. If you use multiple devices to send messages, it is recommended to leave this feature enabled, otherwise, on another device you will not have access to sent messages that were not saved on the remote server. It is also worth noting that POP3 is a one-way only protocol, which means that data is taken from a remote server and sent to the local client.

The default POP3 ports are:

Port 110 – port without encryption

Port 995 is an SSL/TLS port, also known as POP3S

Step 2 - Differences between POP3 and IMAP, and what are the ports for IMAP?

IMAP (protocol application level to access email), just like POP3 is used to receive email messages on a local client, however, it has a significant difference - only the email headers are downloaded, the text of the letter itself remains on the server. This communication protocol works in two directions; if changes occur on the local client, they are transmitted to the server. IMAP has become more popular recently as giant email service providers like Gmail have started recommending it instead of POP3.

The default IMAP ports are:

• Port 143 – port without encryption
• Port 993 is an SSL/TLS port, also known as IMAPS

Step 3 - SMTP, the protocol for outgoing email communications

Simple Mail Transfer Protocol ( SMTP), used to communicate with a remote server and then send messages from local client to the remote server, and ultimately to the server of the message recipient. On your email server, this process is controlled by a special service ( MTA). It's worth mentioning that SMTP is used solely for sending messages.

SMTP ports:

• Port 25 – port without encryption
• Port 465 is an SSL/TLS port, also known as SMTPS

Conclusion

We hope that you now have a clear understanding of how email protocols work and what ports they use. In this tutorial, we learned what POP3, SMTP and IMAP are and what they are used for. For example, POP3 and IMAP are used for the same purposes, but they approach these tasks differently. IMAP leaves the content of the message on the server, and POP3 downloads it to your computer. Also, we found out what standard ports for SMTP, POP3 and IMAP.

(SMTP) is a standard for e-mail. Originally documented in RFC 821 (1982), it was last updated in 2008 with expanded additions of SMTP to RFC 5321 (a widely used protocol today).

Although mail servers and other mail agents use SMTP to send and receive e-mail correspondence, user-class software typically uses SMTP ports only to send data to the server for relaying. To receive messages client applications Typically they use either IMAP or POP3. These protocols are the most convenient and in demand for these purposes: they have advanced functionality and a wide range of capabilities.

Features

SMTP communication between mail servers uses TCP port 25. Mail clients often send outgoing emails to the mail server on port 587. Although legacy mail providers still allow the use of the non-standard port 465 for this purpose.

SMTP connections protected by TLS, known as SMTPS, can be made using STARTTLS technology.

Proprietary and email systems use their own non-standard protocols to access mailboxes on their email servers - all companies use SMTP server ports when sending or receiving email occurs outside of their own systems.

SMTP destination

Almost all actions on the Internet are made possible thanks to protocols - special network rules. software, which allow the computer to communicate with all networks so that users can shop, read news, and send email. Protocols are vital to day-to-day networking—they are built into networking software and used by default.

The SMTP Port Protocol provides a set of codes that facilitate the exchange of email messages between servers ( network computer, which processes incoming and outgoing email). This is a kind of shorthand that allows the server to break down the different parts of the message into categories that another server can understand. When a user sends a message, it turns into lines of text separated by code words (or numbers) that define the purpose of each section.

Technical terminology

SMTP is a TCP/IP protocol used for working with e-mail. However, since it is limited to the ability to send messages to a queue on the receiving end, it is typically used with either POP3 or IMAP, which allows data to be stored on a server and downloaded when necessary. In other words, you typically use an application that selects SMTP for sending e-mail and POP3 or IMAP for receiving correspondence. On Unix based systems, sendmail is the most widely used SMTP server for email. The commercial Sendmail package includes a POP3 server. Microsoft Exchange includes an SMTP server and can also be configured to support POP3.

SMTP is typically used to operate over Internet port 25. An alternative to SMTP that is widely used in Europe is X.400. Many email servers now support Extended Simple Mail Transfer Protocol (ESMTP), which allows you to transfer multimedia files as email.

Story

In the 1960s they used different shapes exchange by email. Users communicated using systems built for specific mainframe computers. Because everything more computers became interconnected, there was a need to develop standards that would allow users different systems send email to each other. SMTP evolved from these standards developed in the 1970s.

Further implementations include the FTP Mail Protocol, starting in 1973. Development work continued into the 1970s until ARPANET became modern Internet in 1980. Then Jon Postel proposed a protocol for transferring mail data.

SMTP began to be widely used in the early 1980s. At that time this protocol was a Unix add-on for the Unix Copy Program mail program. SMTP works best when the sending and receiving machines are connected to the Internet, use a store and send mechanism, and are examples of push technology.

Mail processing model

E-mail is sent by an email client (Mail User Agent, MUA) to a mail server (Mail Submission Agent, MSA) using SMTP on TCP port 587. Most mailbox providers still allow sending to traditional port 25. MSA delivers mail to your mail agent (mail transfer agent, MTA). Often these agents are instances of generic software activated with different settings on the same computer. Local processing can either be done on a single machine or shared across multiple machines. Mail agent processes on the same machine can exchange files, but if processing is running on multiple machines, they pass messages among themselves using an SMTP port, where each machine is configured to use the next machine as the smart host.

Protocol Overview

SMTP is a connection-oriented text protocol in which the sender of mail communicates with the mail recipient by issuing command lines and providing the necessary data through a reliable, orderly data flow channel. An SMTP session consists of commands issued by the SMTP client (initiating agent, sender, or transmitter) and corresponding responses from the SMTP server (listening agent or recipient). A session may include zero or more SMTP transactions, which consist of three command/response sequences:

In addition to the intermediate response for DATA, the response from each server can be either positive or negative (code 2xx). Negative responses can be permanent (codes 5xx) or temporary (codes 4xx). A rejection is a permanent failure and the client must send a rejection message to the server where it received it. A fall is a positive response followed by a rejection of the message.

Mail SMTP ports and their meaning

SMTP is a delivery protocol only. In normal use, mail is sent to the target mail server, such as the mail port SMTP server. Data is routed based on the destination server rather than the individual users it is addressed to. Other protocols (POP or IMAP) are specifically designed for use by individual users, which receive messages and manage mailboxes. SMTP, POP, and IMAP are not acceptable protocols for relaying mail over computers with intermittent connections. They are designed to operate after final delivery, when information is critical to proper operation mail relay has been deleted.

Starting an empty message queue

Remote Message Queue Starting is an SMTP feature that allows a remote host to start mail processing on the server so that it can receive messages intended for it by sending the TURN command. However, this feature posed a potential data security risk and was extended in RFC 1985 by the ETRN command, which operates more securely using an authentication method based on Domain Name System information.

International email address

Users whose script is not Latin, or who use diacritics not in the set ASCII characters, experienced difficulties with the requirement for an email address in the Latin alphabet (mail.ru SMTP port). RFC 6531 was created to address this issue by providing internationalization capabilities for SMTP, an extension to SMTPUTF8, and support for multi-byte and non-ASCII characters in email addresses. Examples: diacritics and other language symbols (Greek and Chinese). Also relevant for Yandex SMTP port.

Current support for this document is at at the moment limited, but there is a lot of interest in widespread adoption of RFC 6531 and related RFCs in countries like China that have a large user base where Latin (ASCII) is a foreign script.

Outgoing mail from SMTP server

The email client must know the IP address of its original SMTP server. This must be specified as part of its configuration (usually DNS name). This server will provide outgoing messages on behalf of the user.

Restrictions on access to the outgoing mail server

Server administrators need to impose certain controls on those clients who can use the server. This helps combat abuse and spam. Similar solutions were widely used:

Previously, many systems imposed restrictions on the use of client location, allowing only use by clients whose IP address was one of the server administrators. Use from any other client IP address is prohibited.

Modern SMTP servers usually offer alternative system, requiring clients to authenticate with credentials before allowing access.

SMTP - what port is used?

Communication between mail servers usually always uses the default value TCP port 25 assigned for SMTP. However, email clients usually use specific smtp ssl ports instead. Most Internet service providers now block all outgoing port traffic from their customers as an anti-spam measure. For the same reason, businesses typically configure their firewall to allow outgoing ports from designated mail servers.

SMTP transport example

A typical example of sending a message via SMTP to two mailboxes(alice and theboss) located in the same mail domain(example.com or localhost.com), is reproduced in the next exchange session. After the sender of the message ( SMTP client) establishes a reliable communication channel for the message receiver (SMTP server), a session is opened with the server, usually containing its full domain name(FQDN), in this case smtp, example or com. The client initiates its dialog box by responding with a HELO command identifying itself in the command parameter with its fully qualified domain name (or an address literal if not available).

Additional extensions

Clients learn which options the server supports by using the EHLO greeting instead of the original HELO. Clients only fall back to HELO if the server does not support SMTP extensions.

Modern clients can use keyword ESMTP extension SSRE for server request for maximum size message that will be received. Old clients and servers may attempt to transmit oversized messages that will be rejected after use network resources, including connection time to network links.

Anti-spam methods and email authentication

The original design of SMTP had no way to identify senders or check whether servers were allowed to send on their behalf. As a result, email spoofing is possible, which is commonly used in email spam and phishing.

Produced special offers to change SMTP or replace them completely. One example of this is Internet Mail 2000, but neither it nor any other achieved much success before the enormous network effect installed base classic SMTP. Instead, mail servers now use a range of methods, including DomainKeys, DomainKeys Identified Mail, Policy Framework and DMARC, DNSBLs and greylisting to reject or quarantine suspicious emails.

Today we will tell you in detail about the most used Internet protocols - POP3, IMAP and SMTP. Each of these protocols has a specific purpose and functionality. Let's try to figure it out.

POP3 protocol and its ports

Post Office Protocol 3 (POP3) is a standard mail protocol designed for receiving emails from a remote server to an e-mail client.POP3 allows you to save an email message to your computer and even read it if you are offline. It is important to note that if you decide to use POP3 to connect to your mail account, emails that have already been downloaded to your computer will be deleted from the mail server. As an example, if you are using several computers to connect to one mail account, then the POP3 protocol may not be best choice in this situation. On the other hand, since mail is stored locally, on a specific user’s PC, this allows optimization disk space on the mail server side.

By default, the POP3 protocol uses the following ports:

• Port 110 is the default POP3 port. Not safe.
• Port 995 – This port should be used if you want to establish a secure connection.

IMAP protocol and ports

Internet Message Access Protocol(IMAP) is an email protocol designed for accessing mail from a local email client. IMAP and POP3 are the most popular protocols on the Internet used for receiving e-mail. Both of these protocols are supported by all modern mail clients(MUA - Mail User Agent) and WEB servers.

While POP3 allows access to mail from only one application, IMAP allows access from multiple clients. For this reason, IMAP is most adaptable in cases where multiple users need access to the same email account.

By default, the IMAP protocol uses the following ports:

• Port 143– default port. Not safe.
• Port 993– port for secure connection.

SMTP protocol and its ports

Simple Mail Transfer Protocol (SMTP) is a standard protocol for sending mail messages via the Internet.

This protocol is described in RFC 821 and RFC 822, first published in August 1982. Within the scope of the RFC data, the address format must be in the format username@domainname. Mail delivery is similar to regular work postal service: for example, a letter to the address [email protected], will be interpreted as follows: ivan_ivanov is the address, and merionet.ru is postal code. If the recipient's domain name is different from the sender's domain name, then the MSA (Mail Submission Agent) will send the letter through the Mail Transfer Agent (MTA). The main idea of ​​MTA is to redirect letters to another domain zone, similar to how traditional mail sends letters to another city or region. An MTA also receives mail from other MTAs.

The SMTP protocol uses the following ports.