When connecting to the Internet the acronym POP stands for Post Office Protocol?

POP3 is an older protocol that was originally designed to be used on only one computer. Unlike modern protocols that use two-way synchronization, POP3 only supports one-way email synchronization, only allowing users to download emails from a server to a client. Because of this, POP3 accounts lack most of the basic functionality that can be found in more modern services, such as:

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IMAP (Internet Messaging Access Protocol)
Technipages Explains POP-3
Common Uses of POP-3
Purpose[edit]
History[edit]
Extensions and specifications[edit]
STARTTLS[edit]
Kerberized Post Office Protocol[edit]
Session example[edit]
Comparison with IMAP[edit]
When connecting to the Internet the acronym POP stands for?
What is known as POP?
What is POP email protocol?
What is POP in cyber security?

The ability to mark a message as read on multiple devices, meaning that every time a user downloads an email onto a different device using POP, it will appear as a new message instead of indicating it was read on another device.
The ability to send items from multiple devices. Sent items cannot be synchronized using POP and can only be saved on the device from which they originated.
Having the ability for emails to be pushed to your device as they arrive. Instead, your device must be set up to automatically check your email server periodically to see if new messages have been received.
Having special folders created or settings set on one device available on all devices using that email account. Using POP, users must manually create or set these individually on all their devices. This means, if users organize their emails on one device, they’ll need to do it again for every other device that uses that POP email account.

IMAP (Internet Messaging Access Protocol)

With IMAP accounts, messages are stored in a remote server. Users can log in via multiple email clients on computers or mobile device and read the same messages. All changes made in the mailbox will be synced across multiple devices and messages will only be removed from the server if the user deletes the email.

POP-3 also spelt POP3 is an acronym for Post Office Protocol. An Internet email standard that specifies how an Internet-connected computer can function as a mail-handling agent; the current version is called POP-3. Messages arrive at a user’s electronic mailbox, which is housed on the service provider’s computer. From this central storage point, one can access his or her mail from different computers, a networked workstation in the office, as well as a PC at home.
An alternative protocol is IMAP, in which all of a user’s mail is stored at a central location rather than downloaded. IMAP is significantly more convenient for mobile users than POP-3. See email, IMAP.

Technipages Explains POP-3

POP-3 is an abbreviation for post office protocol 3; it is an internet protocol for receiving electronic mails. The protocol is maintained and handled by an internet server, where emails are retained on the internet server until they are downloaded from the server. After the message has been downloaded, they don’t require an internet connection to access the downloaded mails as they are stored in an offline medium. POP-3 is the most used email retrieval protocol, and it is currently being rivalled by IMAP (internet message across protocol). While POP-3 was designed to be accessed by a user by using a single computer, IMAP allows for access across multiple computers.
Post office protocol was developed in 1984, and back then it was known as POP. POP was updated to POP-2 in 1985, while POP-3 was designed in 1988, it is an update to POP-2, ever since 1985, and there has been no other update to the post office protocol. It is important to note that Post office protocol 3 (POP-3) has no means of sending a message or replying the messages received on the server.

Common Uses of POP-3

For HTTP, POP3, SMTP, IMAP or NNTP protocol traffic detection,traffic performance will be redirected to the appropriate component.
This is a journal that discusses the theory, running procedure and standard commands of POP3 protocol
It is advised to read the official POP3 specification, RFC1939 from IETF: Post Office Protocol – Version 3.

In PoP displays, the pictures are given equal size and dimensions, so they are particularly common amongst security monitoring systems or other environments where multiple views need to be monitored with equal attention. Some televisions also allow PoP displays. Medical and dental software can also compare two or more images side by side, such as x-rays or other scans.

In computing, the Post Office Protocol (POP) is an application-layer Internet standard protocol used by e-mail clients to retrieve e-mail from a mail server.[1] POP version 3 (POP3) is the version in common use, and along with IMAP the most common protocols for email retrieval.
Purpose[edit]
The Post Office Protocol provides access via an Internet Protocol (IP) network for a user client application to a mailbox (maildrop) maintained on a mail server. The protocol supports download and delete operations for messages. POP3 clients connect, retrieve all messages, store them on the client computer, and finally delete them from the server.[2] This design of POP and its procedures was driven by the need of users having only temporary Internet connections, such as dial-up access, allowing these users to retrieve e-mail when connected, and subsequently to view and manipulate the retrieved messages when offline.
POP3 clients also have an option to leave mail on the server after download. By contrast, the Internet Message Access Protocol (IMAP) was designed to normally leave all messages on the server to permit management with multiple client applications, and to support both connected (online) and disconnected (offline) modes of operation.
A POP3 server listens on well-known port number 110 for service requests. Encrypted communication for POP3 is either requested after protocol initiation, using the STLS command, if supported, or by POP3S, which connects to the server using Transport Layer Security (TLS) or Secure Sockets Layer (SSL) on well-known TCP port number 995.
Messages available to the client are determined when a POP3 session opens the maildrop, and are identified by message-number local to that session or, optionally, by a unique identifier assigned to the message by the POP server. This unique identifier is permanent and unique to the maildrop and allows a client to access the same message in different POP sessions. Mail is retrieved and marked for deletion by the message-number. When the client exits the session, mail marked for deletion is removed from the maildrop.
History[edit]
The first version of the Post Office Protocol, POP1, was specified in RFC 918 (1984) by Joyce K. Reynolds. POP2 was specified in RFC 937 (1985).
POP3 is the version in most common use. It originated with RFC 1081 (1988) but the most recent specification is RFC 1939, updated with an extension mechanism (RFC 2449) and an authentication mechanism in RFC 1734. This led to a number of POP implementations such as Pine, POPmail, and other early mail clients.
While the original POP3 specification supported only an unencrypted USER/PASS login mechanism or Berkeley .rhosts access control, today POP3 supports several authentication methods to provide varying levels of protection against illegitimate access to a user's e-mail. Most are provided by the POP3 extension mechanisms. POP3 clients support SASL authentication methods via the AUTH extension. MIT Project Athena also produced a Kerberized version. RFC 1460 introduced APOP into the core protocol. APOP is a challenge–response protocol which uses the MD5 hash function in an attempt to avoid replay attacks and disclosure of the shared secret. Clients implementing APOP include Mozilla Thunderbird, Opera Mail, Eudora, KMail, Novell Evolution, RimArts' Becky!,[3] Windows Live Mail, PowerMail, Apple Mail, and Mutt. RFC 1460 was obsoleted by RFC 1725, which was in turn obsoleted by RFC 1939.
POP4 exists only as an informal proposal adding basic folder management, multipart message support, as well as message flag management to compete with IMAP; however, its development has not progressed since 2003.[4]
Extensions and specifications[edit]
An extension mechanism was proposed in RFC 2449 to accommodate general extensions as well as announce in an organized manner support for optional commands, such as TOP and UIDL. The RFC did not intend to encourage extensions, and reaffirmed that the role of POP3 is to provide simple support for mainly download-and-delete requirements of mailbox handling.
The extensions are termed capabilities and are listed by the CAPA command. With the exception of APOP, the optional commands were included in the initial set of capabilities. Following the lead of ESMTP (RFC 5321), capabilities beginning with an X signify local capabilities.
STARTTLS[edit]
The STARTTLS extension allows the use of Transport Layer Security (TLS) or Secure Sockets Layer (SSL) to be negotiated using the STLS command, on the standard POP3 port, rather than an alternate. Some clients and servers instead use the alternate-port method, which uses TCP port 995 (POP3S).
Demon Internet introduced extensions to POP3 that allow multiple accounts per domain, and has become known as Standard Dial-up POP3 Service (SDPS).[5] To access each account, the username includes the hostname, as john@hostname or john+hostname.
Google Apps uses the same method.[6]
Kerberized Post Office Protocol[edit]
In computing, local e-mail clients can use the Kerberized Post Office Protocol (KPOP), an application-layer Internet standard protocol, to retrieve e-mail from a remote server over a TCP/IP connection. The KPOP protocol is based on the POP3 protocol – differing in that it adds Kerberos security and that it runs by default over TCP port number 1109 instead of 110. One mail server software implementation is found in the Cyrus IMAP server.
Session example[edit]
The following POP3 session dialog is an example in RFC 1939:[7]
```
S: 
C: 
S:    +OK POP3 server ready <[email protected]>
C:    APOP mrose c4c9334bac560ecc979e58001b3e22fb
S:    +OK mrose's maildrop has 2 messages (320 octets)
C:    STAT
S:    +OK 2 320
C:    LIST
S:    +OK 2 messages (320 octets)
S:    1 120
S:    2 200
S:    .
C:    RETR 1
S:    +OK 120 octets
S:    
S:    .
C:    DELE 1
S:    +OK message 1 deleted
C:    RETR 2
S:    +OK 200 octets
S:    
S:    .
C:    DELE 2
S:    +OK message 2 deleted
C:    QUIT
S:    +OK dewey POP3 server signing off (maildrop empty)
C: 
S: 
```
POP3 servers without the optional APOP command expect the client to log in with the USER and PASS commands:
```
C:    USER mrose
S:    +OK User accepted
C:    PASS tanstaaf
S:    +OK Pass accepted
```
Comparison with IMAP[edit]
The Internet Message Access Protocol (IMAP) is an alternative and more recent mailbox access protocol. The highlights of differences are:

When connecting to the Internet the acronym POP stands for?

On the Internet, a point-of-presence (POP) is an access point from one place to the rest of the Internet. (POP also stands for the e-mail Post Office Protocol; see POP3.) A POP necessarily has a unique Internet Protocol (IP) address.

What is known as POP?

A point of purchase (POP) is a term used by marketers and retailers when planning the placement of consumer products, such as product displays strategically placed in a grocery store aisle or advertised in a weekly flyer.

What is POP email protocol?

POP3 (Post Office Protocol) POP3 is an older protocol that was originally designed to be used on only one computer. Unlike modern protocols that use two-way synchronization, POP3 only supports one-way email synchronization, only allowing users to download emails from a server to a client.

What is POP in cyber security?

5. Definition(s): A mailbox access protocol defined by IETF RFC 1939. POP is one of the most commonly used mailbox access protocols.