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.
POP3– an application-level Internet protocol that provides access to the mail server via TCP/IP and using port 110.
IMAP– an application-level Internet protocol that provides access to the mail server via TCP and using port 143.
Difference between POP3 and IMAP
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 local computer, are disabled after the operation is completed and further work programs take place offline. 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 the network condition and demonstrates relatively long time response.
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. Automatic removal There are no messages from the server.
Another important difference between IMAP and POP3 is the ability to extend the IMAP protocol and ultimately receive 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.
TheDifference.ru determined that the difference between IMAP and POP3 is as follows:
IMAP uses port 143, POP3 uses port 110.
IMAP works both online and offline, POP3 works only offline.
IMAP allows you to manage messages directly on the server, POP3 downloads files to the user's local computer.
POP3 provides faster access
In IMAP, you can configure the separation of access rights.
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 mail client, which pumps out all new mail on 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 time connections 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 protocols public access to files (these protocols do not exist on every platform, they can be inferior in performance and cause file locking problems. All this is not necessary for those users who always use the same computer to access mail, but it becomes very important for those who use multiple computers.
Opportunities and
POP was designed to support offline mail processing. And although offline access restrictions can be compensated by using this protocol in online mode 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 available 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 many mailboxes(possibly even hierarchical).
- 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 status 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 the user's personal settings, e.g. 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.
IMAP list software can be found at /go?www.imap.org/products.html, and a list of documents related to IMAP 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 more full description 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).
This article covers the most commonly used protocols email on the Internet - POP3, IMAP and SMTP. Each of them has a specific function and way of working. The content of the article explains which configuration is best suited for the user's specific needs when using an e-mail client. It also reveals the answer to the question of what protocol e-mail supports.
What is POP3?
Protocol Version 3 (POP3) is a standard email protocol used to receive email from a remote server to a local email client. Allows you to download messages to your local computer and read them even if the user is in offline mode. Please note that when you use POP3 to connect to your account, messages are downloaded locally and deleted from the email server.
By default, the POP3 protocol runs on two ports:
port 110 is an unencrypted POP3 port;
port 995 - this should be used if you want to connect to POP3 securely.
What is IMAP?
Internet Message Access Protocol (IMAP) is an email protocol used to access email. remote web server from local client. IMAP and POP3 are the two most commonly used protocols for receiving emails and are supported by all modern email clients and web servers.
The POP3 protocol means that your email address is accessible only from one application, while IMAP allows simultaneous login from several clients at once. That's why IMAP fits better, if you plan to access your email from different places or if your messages are managed by multiple users.
The IMAP protocol runs on two ports:
port 143 is the default unencrypted IMAP port;
port 993 - this must be used if you want to connect securely using IMAP.
What is SMTP?
The protocol is a standard protocol for sending email over the Internet.
SMTP operates on three ports:
port 25 is unencrypted by default;
port 2525 - this is opened on all SiteGround servers if port 25 is filtered (for example by your ISP) and you want to send unencrypted emails using SMTP;
port 465 - This is used if you want to send messages securely using SMTP.
What protocols are used to exchange email? Concepts and terms
The term email server refers to the two servers required to send and receive emails, i.e. SMTP and POP.
The incoming mail server is the server associated with your email address account. It cannot have more than one incoming mail server. To access incoming messages, you need an email client—a program that can receive email from an account, allowing the user to read, forward, delete, and reply to messages. Depending on your server, you may be able to use a dedicated email client (such as Outlook Express) or a web browser. So, Internet Explorer used to access email-based accounts. Messages are stored on the incoming mail server until it is downloaded. Once you have downloaded your mail from the mail server, you cannot do it again. To successfully download data, you must enter correct settings in an email program. Most incoming mail servers use one of the following protocols: IMAP, POP3, HTTP.
Outgoing mail server (SMTP)
This is a server used only for sending emails (to transfer them from your email client program to the receiver). Most outgoing mail servers use Protocol) to send correspondence. Depending on your network parameters The outgoing mail server may belong to your ISP or the server on which you configure your account. Alternatively, you can use a subscription-based SMTP server that will allow you to send emails from any account. Due to spam issues, most outgoing email servers do not allow you to send emails unless you are logged into their network. A server with an open relay will allow you to use it to send emails, regardless of whether you belong to it network group or not.
Email Ports
For networks, a port means the end point of a logical connection. The port number determines its type. The following are the default email ports:
POP3 - port 110;
IMAP - port 143;
SMTP - port 25;
HTTP - port 80;
secure SMTP (SSMTP) - port 465;
secure IMAP (IMAP4-SSL) - port 585;
IMAP4 over SSL (IMAPS) - port 993;
Secure POP3 (SSL-POP) - port 995.
Email protocols: IMAP, POP3, SMTP and HTTP
Basically, a protocol refers to a standard method used at each end of a communication channel. To deal with email, you must use a special client to access the mail server. In turn, they can exchange information with each other using completely different protocols.
IMAP protocol
IMAP (Internet Message Access Protocol) is a standard protocol for accessing email from your local server. IMAP is a client/server protocol in which email is received and data is stored by your Internet server. Since it only requires a small data transfer, it works well even on a slow connection, such as a modem connection. When attempting to read a particular email message, the client downloads data from the server. You can also create and manage folders or mailboxes on the server, and delete messages.
POP3 protocol
POP (Post Office Protocol 3) e-mail provides a simple, standardized way for users to access their mailboxes and download messages to their computers.
When using the POP protocol, all your email messages will be downloaded from the mail server to your local computer. You can also leave copies of your emails on the server. The advantage is that after downloading your messages, you can disconnect your Internet connection and read your email at your leisure without having to resort to additional expenses to get in touch. On the other hand, with this protocol you receive and download a lot of unwanted messages (including spam or viruses).
SMTP protocol
The protocol is used by a mail transfer agent (MTA) to deliver electronic messages to a specific recipient server. SMTP can only be used to send emails, not to receive them. Depending on your network or ISP settings, you may only be able to use the SMTP protocol under certain conditions.
HTTP protocols
HTTP is not a protocol designed for email communications, but it can be used to access your mailbox. It is also often called web email. It can be used to compose or receive emails from your account. Hotmail - good example using HTTP as an email protocol.
Managed File Transfers and Network Solutions
Your ability to send and receive email is primarily due to three TCP protocols. They are SMTP, IMAP and POP3.
SMTP
Let's start with SMTP because its main function is different from the other two. SMTP, or Simple Mail Transfer Protocol, is primarily used for sending email from an email client (such as Microsoft Outlook, Thunderbird or Apple Mail) to your email server. It is also used to relay or forward mail messages from one mail server to another. This is necessary if the sender and recipient have different email service providers.
SMTP, which is specified in RFC 5321, uses port 25 by default. It can also use port 587 and port 465. The latter, which was introduced as the port of choice for secure SMTP (a.k.a. SMTPS), is considered deprecated. But in fact, it is still used by several email service providers.
POP3
Protocol post office, or POP, is used to retrieve email messages from Latest version The one that is widely used is version 3, hence the term "POP3".
POP version 3, specified in RFC 1939, supports extensions and several authentication mechanisms. Authentication features are required to prevent malicious users from accessing user communications.
The POP3 client receives email as follows:
connects to the mail server via port 143 (or 993 for SSL/TLS connections);
retrieves email messages;
serves to connect before closing the mail client application and download messages on demand.
connects to the mail server on port 110 (or 995 for SSL/TLS connections);
deletes copies of messages stored on the server;
disconnects from the server.
Although POP clients can be configured to allow the server to continue to store copies of downloaded messages, the steps described above are common practice.
IMAP
IMAP, especially current version(IMAP4), is a more complex protocol. This allows users to group related messages and place them in folders, which in turn can be organized hierarchically. It is also equipped with message flags that indicate whether the message has been read, deleted, or received. It even allows users to search server mailboxes.
Operation logic (imap4 settings):
Please note that messages are not deleted on the server. This can have serious consequences. IMAP specifications can be found in RFC 3501.
Choosing between IMAP and POP3
Since the core function of SMTP is fundamentally different, the dilemma of choosing the best protocol usually involves only IMAP and POP3.
If server storage space is important to you, then choose POP3. A server with limited memory is one of the main factors that may force you to support POP3. Because IMAP leaves messages on the server, it can consume memory space faster than POP3.
If you want to access your mail at any time, then it is better to stick with IMAP. There is one good reason why IMAP was designed to store messages on a server. It is used to search for messages from multiple devices - sometimes even simultaneously. So if you have an iPhone, Android tablet, laptop and desktop and you want to read email from any or all of these devices, then IMAP will be the best choice.
Synchronization is another advantage of IMAP. If you access email messages from multiple devices, you'll likely want them all to show any activity you've performed.
For example, if you read messages A, B, and C, you want them to also be marked as read on other devices. If you have deleted letters B and C, then you will want the same messages to be deleted from your inbox on all gadgets. All these synchronizations can only be achieved if you use IMAP.
Since IMAP allows users to organize messages hierarchically and place them in folders, it helps users better organize their correspondence.
Of course, everything functionality IMAPs come at a price. These solutions are more difficult to implement and the protocol ends up consuming a lot more CPU and RAM, especially when it performs the synchronization process. In fact, high CPU and memory usage can happen on both the client and server side if there are a ton of messages to sync. From this point of view, the POP3 protocol is less expensive, although less functional.
Privacy is also one of the issues that will greatly depend on the end users. They would generally prefer to download all email messages and not leave copies of them on an unknown server.
Speed is an advantage that varies and depends on the situation. POP3 has the ability to download all mail messages when connected. And IMAP can, if necessary (for example, when there is insufficient traffic), download only message headers or certain parts and leave attachments on the server. Only when the user decides that the remaining parts are worth downloading will they become available to him. Therefore, IMAP can be considered faster.
However, if all messages on the server must be downloaded every time, then POP3 will be much faster.
As you can see, each of the described protocols has its own advantages and disadvantages. It's up to you to decide which features or capabilities are more important.
Also, the desired method of accessing the e-mail client determines the preferred protocol. Users who only work from one machine and use webmail to access their new emails will appreciate POP3.
However, users who share mailboxes or access their emails with different computers, will prefer IMAP.
Spam firewalls with SMTP, IMAP and POP3
Most spam firewalls only deal with and protect the SMTP protocol. The servers send and receive SMTP email and these will be checked by the spam firewall on the gateway. However, some spam firewalls provide the ability to protect POP3 and IMAP4 when external users need these services to access their email.
SMTP firewalls are transparent to end users; There are no configuration changes for clients. Users still receive and send email messages to the email server. Thus, Exchange or Dominos must configure routing of messages to the firewall based on a proxy server when sending email, and also provide the ability to send emails from the firewall.
Articles and Lifehacks
Understand, how to set up mail on android, not difficult at all. By following the step-by-step instructions outlined in this article, you will be able to do this completely independently, no less than installing it.
Setting up an email account on a device under Android control, occurs through mail program, which can be found in the list of already installed on Android programs. It is indicated by a postal envelope icon. Setting up your email inbox starts with finding this icon. Next, you need to follow the step-by-step instructions below, as with.
Step by step instructions how to set up mail on android
Step #1. Launching the mail program.
Launch your email program by clicking on the email icon.
Step #2. Setting up a username and password.
In the “E-mail” line, write down the full desired address of your future email in the following form: “[email protected]”).
In the “Password” line, enter a combination of characters that will serve as the login password to the mailbox you created. It is desirable that, in addition to Latin letters (uppercase and lowercase), it contains numbers and other characters that can be “represented” using the keyboard.
Step #3. Setting up your incoming mail server.
In the "Select account type" window you will be presented with three options:
- IMAP;
- POP3;
- Exchange.
Let's consider one of them. Let's say you chose the "POP3" protocol. You will need to follow the following directions:
- in the completed “Username” field, nothing needs to be changed;
- the entry hidden by the “******” symbols in the “Password” field will also not need to be changed;
- in the “POP3 Server” field you will need to enter “pop.mail.ru”;
- in the “Port” field, from the proposed options, it is best to select a protected one – “995”;
- in the “Security Type” field, select an entry with six Latin letters and a slash between them: SSL/TLS;
- in the “Delete messages from the server” field, it is advisable to select “never” - this means that the messages you receive will be saved on the mail.ru server;
- click “Next”.
Step #4. Setting up the outgoing message server for your mail.
- the “SMTP” field must be filled with the entry “smtp.mail.ru”;
- field “Port” - numbers 465;
- in the “Security Type” field, select six Latin letters with a slash between them: SSL/TLS;
- in the “Username” and “Password” fields leave everything as it is, you don’t need to change anything;
- click “Next”.
If you correctly understood how to set up mail on Android and followed the instructions, then your device should be ready to receive and send email messages.
You may have already heard about the terms POP3, IMAP and Exchange and know that it has something to do with email. But what exactly is it and what benefit or difference does it make for me?
We need to tell you up front that all three of these terms are related with email search. It makes no difference which program you use (eg: Microsoft Outlook, Thunderbird, etc.). However, it has something to do with the features that the email server can provide (or has provided) to you.
POP 3 - features, advantages and disadvantages
Pop3 - most old way receive email. Almost all mail server providers make this service available to everyone. Here emails are retrieved from the mailbox and saved on the computer.
There are also configuration options, so emails stay on mail server when receiving email. However, this often becomes a problem because the storage space for these POP3 email accounts is usually very small.
The main downside in addition to some nice features is that once the emails have been retrieved, they are located on the device ( personal computer/ laptop).
If this device is suddenly broken (for example, hard drive), all emails will disappear. So, there is always something to consider to ensure the security of these emails.
You should use POP3 if:
- The size of your registered mailbox is relatively small and there is a need quick access to him.
- Too many features They are holding you back or just annoying you.
- You still only use one device to receive email.
- Temporarily storing your email messages on a server is sufficient.
- You prefer to have your data only locally with you.
IMAP - features, advantages and disadvantages
IMAP is much more best way receive your emails. However, this method is not supported by every mail server.
IMAP syncs all emails and their email server folders. If you move an email to a subfolder, the subfolders and the email will also be on the email server.
If your computer or laptop breaks, you won't have to worry about it and just need to set up a new device and all emails will be returned.
In your client, select the SENT folder as the location for sent messages.
This way, you can also see sent messages on all devices (they are stored locally by clients by default).
You should use IMAP if:
- You have several devices that you need to use and that they have the same state.
- You want to access the mailbox of several employees at the same time.
- Used your hierarchical mailboxes directly on the email server.
- Do you need access multiple mailboxes during a session.
- You need a backup on your email server.
- You need to access your current emails from third party device via the web administrator.
Exchange - features, advantages and disadvantages
When receiving mail using the Exchange RPC protocol all information in Outlook is synchronized, including calendars and contacts. Permissions and releases from other users are possible, etc.
Anyone who has ever experienced Exchange will never use another service again. Here's a small example.
Have you also integrated your Exchange Server on your own mobile phone. Of course, all contacts, calendar and emails are synced here too. Now you have changed your mobile phone and the only thing you need to do is set up your email account on the new device. Now all data will be available to you again.
For this service there is now several providers such as Microsoft, with Office product 365, but many local providers also offer this for a monthly fee.
You should use Exchange if:
- you want to manage together with other resources;
- you also want to sync your contacts;
- you need access to your calendars everywhere;
- do you need easy setup in the client;
- for you important backups all data;
- you want to use an additional service address, such as OWA (Outlook Web Access);
- you want to manage your messages through your client;
- you need several mailboxes in your organization;
- POP3 and IMAP are not enough for you.
