What does account type pop3 or imap mean? How to set up mail on Android

There are two main methods of working with mail: Online and Offline.

According to the offline method, mail is delivered to the server, and the PC user periodically launches an email client, which downloads all new mail to the PC. All mail processing, such as filtering, occurs on the local machine. Offline access? a “store and forward” service designed to forward mail on demand from a mail server to a single endpoint machine. Once delivered to the destination machine, the messages are deleted from the mail server.

In the case of online access, mail is also delivered to the shared server, but the client no longer copies all mail and then deletes it from the server. The online approach is more client-server. In this case, the client can ask the server for the header of the message or request that the message be searched by some criterion. Messages can be marked with various status flags (for example, the message has been marked for deletion or a reply has been sent to it) and these marks are retained until they are explicitly deleted by the user (which may not happen until the next session).

• Advantages of the offline method:
  • Minimum connection time to the server.
  • Minimal use of server resources.

• Advantages of the online method:
  • Ability to use different computers at different times.
  • Ability to use?lightweight? client machines.
  • Platform-independent access to multiple mailboxes.
  • Possibility of simultaneous access to shared mailboxes.

The main advantage of online access is that mailboxes with incoming and archive mail are stored on the server and can be accessed uniformly from different computers at different times. And all this can be done without using file sharing protocols (these protocols do not exist on every platform, can be inferior in performance and cause file locking problems). All this is not necessary for those users who always use the same same computer for accessing mail, but becomes very important for those who use multiple computers.

Opportunities and

POP was designed to support offline mail processing. Although the limitations of offline access can be compensated for by using this protocol online, POP simply does not have some of the functionality required for high-quality online access. The pseudo-online access mode supported by POP3 is where the user leaves mail on the server and this often requires a remote file system protocol in order for the mail client to update the mailbox or set message flags. IMAP can also be used for offline access, but its power manifests itself primarily with online access. In a nutshell, IMAP allows you to manipulate remote mailboxes as if they were local. Depending on the IMAP client implementation and the mail architecture that the mail system manager wishes to have, the user may store messages only on the client machine, only on the server, or have the choice to do both.

Let us now give a brief comparison of the POP3 and IMAP4 protocols.

• Characteristics common to both protocols
  • Both support offline access
  • Mail is delivered to a shared, always-on mail server
  • New mail is accessible from more client platforms and from anywhere on the web
  • The protocols are open and standardized (there are corresponding RFCs on the Internet)
  • Focused only on reading mail, both use
  • Both protocols support persistent message IDs (POP3 - not all servers) which are used for disconnected access

• Benefits of POP3
  • Easier to implement
  • More clients exist at the moment

• Benefits of IMAP4
  • Can manipulate persistent message flags (Seen, Draft, Deleted,?).
  • It can both store messages and download them. It is possible to add messages to your mailbox.
  • Can work with multiple mailboxes (possibly even hierarchical ones).
  • Can support parallel access to mailboxes and parallel updating of mailboxes.
  • Suitable for accessing non-mail data, such as news or documents.
  • Can use offline access to reduce connection time and used disk space.
  • Allows you to search for messages on the server.
  • It is possible to download part of a letter, and you can download a fragment starting from any place and of any length.
  • Designed specifically to improve online access performance, especially for slow connections.
  • IMAP4 rev 1 supports the Unicode standard (mailboxes with Unicode names, message search)
  • There is a standardized way to extend the basic protocol. In particular, there are extensions for managing user quotas and their access rights to other people's or shared mailboxes.
  • Are there ?companion protocols? (IMSP and its ACAP receiver) to store and manipulate user settings.

More about IMAP4

IMAP can manipulate persistent message status flags, including ?Seen?, ?Deleted?, ?Answered?, as well as user-defined flags. IMAP allows you to store messages and also receive them from the server. A user can add a message from an inbox to an archive box (or vice versa). Using IMAP, a client can access and manage multiple mailboxes. This includes both the ability to name and access various archive and inboxes, as well as the ability to list, create, delete, and rename them. These mailboxes can be located on the same or on different mail servers. An IMAP client can allow you to see them all at once and move messages from one mailbox to another.

IMAP can allow simultaneous access and updating of shared mailboxes. This ability is convenient if several clients process messages arriving in a common inbox. All active clients are notified of mailbox state changes via IMAP.

IMAP can be used to access non-mail data, such as Newsgroups. This is convenient from the point of view of unifying the method of access to various classes of information. IMAP also supports offline access, which saves connection time to the server and server resources. The offline method is convenient to use in situations where access to the server occurs only over an expensive dial-up connection and multi-platform access to any mailbox is not required. It is also beneficial to use such access if the client machine is rich in resources and the server is poor.

Not all IMAP clients offer support for offline mode, but the protocol fully allows it. IMAP has a companion protocol for managing user settings called IMSP, Internet Message Support Protocol. IMSP enables location-independent (multi-platform) access to a user's personal settings, such as the address book. (Its descendant ACAP also allows you to store settings for servers and user groups. ACAP is specially optimized to reduce the amount of data sent over the network, has rich search capabilities on the server side, and allows you to manage data access rights.)

IMAP has designs to optimize online access, especially over low-speed links. These designs include the ability to obtain the structure of a message without downloading the entire message to the client machine, selective downloading of parts of a message, and the ability to use the server for lookup to reduce the amount of data transferred between the client and server. It can be very useful to delay sending some messages or parts of them (from the server to the client machine) until the appropriate moment, if the messages are not of immediate interest. If the message contains attached documents or multimedia data, transmitting only part of the message can be a big advantage. This can be felt quite clearly, for example, if you are in a hotel and they send you a short message with a 10 MB video clip attached.

Efficient handling of MIME messages is a significant advantage of IMAP over POP. (MIME stands for Multipurpose Internet Mail Extensions, a standard for encoding messages containing arbitrary file attachments. Once MIME messages are encoded, they can be sent using SMTP.) To summarize, we can say that

IMAP beats POP in three areas:

• richer functionality for mailbox manipulation;
• the ability to manage several mailboxes rather than just one;
• primitives for optimizing online access performance, especially when it comes to large MIME messages.

Advantages of POP over IMAP:

• the presence of a larger number of implementations, both clients and servers;
• ease of setup (since POP has little functionality, you don’t need to configure anything).

In my opinion, over time, IMAP should supplant POP. A description of POP3 can be found in RFC-1939. IMAP4 is described in RFC-2060.

A list of IMAP software can be found at /go?www.imap.org/products.html, and a list of IMAP-related documents can be found at /go?www.imap.org/biblio.html.

Also of potential interest may be /go?www.imap.org/imap.docs.html (a collection of IMAP documents); Message Access Paradigms and Protocols (this document is a more complete description of the ideas presented in the article, in addition, it describes in detail the terminology and provides information about the POP and IMAP protocols in the context of online access).

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 multiple computers to connect to one email account, then POP3 may not be the best choice in this situation. On the other hand, since mail is stored locally, on a specific user’s PC, this allows you to optimize disk space on the mail server side.

By default, the POP3 protocol uses the following ports:

• Port 110 is the default POP3 port. It is 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 mail access 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 the regular 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 the 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.

Everyone knows how to work with email. We open the browser, look for the required resource, log in and read the incoming email correspondence. The pop3 and imap mail protocols allow you to work with mail without a browser, through client programs, as if the files were located directly on the local computer.

Definition

POP3 is an application-level Internet protocol that provides access to the mail server via TCP/IP and using port 110.

IMAP is an application-level Internet protocol that provides access to the mail server via TCP and using port 143.

Comparison

The difference between POP3 and IMAP is application-specific. Both protocols perform identical tasks, only POP3 allows you to download all files at once (correspondence is stored in these files), and IMAP first allows you to download a list of files and then selectively download them yourself. This is the main difference between the protocols, and the newer IMAP was created precisely to implement this difference: clients were not satisfied with the need to parse mail locally, while on the server the files were deleted after downloading. On IMAP servers, the user manages his messages independently.

pop3 clients connect to the network only to download files to the local computer, disconnect after the operation is completed, and further program operation takes place in offline mode. IMAP clients can work offline, but online provides more options for them: for example, managing messages on the server. As a result, offline access requires fewer resources and is faster, while online access is more dependent on network conditions and exhibits a relatively long response time.

POP3 assumes monouser access to a mailbox, IMAP allows multiple clients to connect to it, while the work of any of them is not limited, and everyone sees the changes made by others. IMAP also allows the user to see the status of messages, move them, create folders and delete them as if he were dealing with a local copy. Messages are not automatically deleted from the server.

Another important difference between IMAP and POP3 is the ability to expand the IMAP protocol and ultimately obtain fine-tuning, for example, client access rights to the server. Despite the fact that POP3, due to its longevity, is more widespread and easier to configure, IMAP seems more convenient when solving many problems, for example, corporate ones.

Conclusions website

1. IMAP uses port 143, POP3 uses port 110.
2. IMAP works both online and offline, POP3 works only offline.
3. IMAP allows you to manage messages directly on the server, POP3 downloads files to the user's local computer.
4. POP3 provides faster access
5. In IMAP, you can configure the separation of access rights.

If you receive some emails on one PC and others on another, this can cause problems. Since it does not use the IMAP protocol.

Wayne Zimmerman's wife usually reads email on her PC. But when she tries to view her email on her husband's computer, the messages are lost.

I can assume that your wife's email client is configured to use the legacy POP3 protocol. It worked fine when most people had one computer and not a smartphone. But as people use multiple computers and mobile devices to access their email, this is no longer the case.

When you tell your email client ( for example Outlook) receive mail, the POP3 protocol moves new letters from the mail service server to your client, and deletes them from the server. If you check email on two computers using POP3, some emails will be accessible on one computer, but other emails will only be accessible on the other.

Here are two ways to work around this problem:

Use the best protocol

Unlike POP3, IMAP is used to synchronize client software with the server. All emails will be available on both devices. When you delete an email in your client, IMAP also deletes it from the server.

In Outlook 2016 ( which by default uses the POP3 protocol), you cannot directly change the account protocol. But you can create a new account and delete the old one:

1. In Outlook, go to menu File - Account Settings - Account Settings:

1. A dialog box will appear on the screen: Account settings" Click on the “Create” button;
2. In the master " Add an account» select the item « Manual setting" or " Additional server types» ( in the lower left corner):

1. On the next page, select POP or IMAP protocol. ( Yes, this is one of the options);
2. Provide all required information. Make sure your account type is set to IMAP;
3. You now have two accounts that share the same email address. Go back to your inbox and drag emails from your old account to your new one;
4. Return to the "Accounts" dialog box, select the old account configured for POP3, and click on the "Delete" button.

Use web client

If you check your mail through an email service and not through a program on your PC, downloading letters to a particular computer is not a problem.

You can also use a trusted web email service such as Gmail. You'll need to create a new Gmail account, but you can set up Gmail to send and receive emails from any other email service by setting it up using IMAP:

1. In Gmail, click on the tool icon located in the upper right corner and select “Settings";
2. Go to the " Accounts and Import»;
3. In chapter " Send email as» click on the button « Add another email address» and follow the instructions of the setup wizard;
4. Go to the section " Checking mail from other accounts (using POP3)", click on the button " Add a POP3 email account» and follow the instructions of the setup wizard.

Currently, there are a lot of methods of communication via the Internet. You can use ICQ or Skype, social networks, and other resources. About two decades ago, the only way to send or receive virtual mail was through email.

Until a certain time, servers processing user letters had limited capabilities. Storing large amounts of information was expensive, which meant deleting the message from the disk as soon as it was downloaded to the client's computer. Progress has moved forward, there are more opportunities, the user can store letters in a mailbox on a central server for an unlimited amount of time, and carry out various operations with them.

Data transfer protocols used when working with email

Any form of communication has a certain style – a set of agreements. On the network it is a protocol. When working with E-mail, a number of protocols can be used. Among them:

• POP3;
• IMAP.

What is the difference, which protocol and in which case is it advisable to use it?

What is POP3

Wanting to send a letter or access a personal mailbox located on a remote server, the user can use the browser installed on the computer, which is not entirely convenient. More often used, which exchanges information with the server using a specific protocol. If it is Post Office Protocol, the process is as follows:

1. Compound;
2. The client receives information about the status of the mailbox, downloads letters;
3. Updating the server and deleting selected messages;
4. Closing the connection.

What is IMAP

The IMAP protocol provides the user with more options. After authorization on the mail resource, only the headers of the letters are downloaded to the computer. When you select the desired message, the client program downloads the entire letter. At the same time, you can work on-line and off-line. Read messages are not deleted; you can perform desired operations with them in the future.

Pros and cons of IMAP and POP3

Which protocol to choose? It all depends on the specifics of the job and needs.

In addition to the fact that messages are saved on the server without being deleted, the advantages of IMAP include:

• Possibility of access to the mailbox from several clients;
• Supports simultaneous access of multiple clients;
• Supports multiple boxes;
• Ability to create new folders that can be accessed by other users;
• Ability to mark emails as read, important, and others;
• Server search support;
• Possibility of working in on-line mode.

The only downside in this case is that the user spends more time downloading letters from the central computer.