Mail protocols and Ports

e-mail protocol has SMTP, POP2, POP3, IMAP4, etc., are subordinate to the TCP/IP protocol cluster, by default, the connection is established through TCP ports 25, 110 and 143 respectively. For different purposes and functions, we will adjust the mail server settings to suit your needs.

Yesterday Foxmail suddenly broke down, I checked for a long while to find the reason, re-installed after the message and the client mail messages on the Web are inconsistent. Also fortunately inconsistent, otherwise priceless data mail is gone.

First of all, talk about the agreement, the commonly used mailbox protocol has the following types:

(1) SMTP (Simple Mail Transfer Protocol), which is simply the message Transfer Protocol.

It is a set of rules for sending mail from the source address to the destination, and it controls the way the letters are relayed. belongs to the TCP/IP protocol family, which helps each computer find the next destination when sending or relaying letters.

(2) POP (postoffice Protocol), which is the Post Office Protocol.

The POP protocol is responsible for retrieving e-mail from the mail server. Only new messages are retrieved from the mail server, and when the user reads the message, the POP command all the message information is immediately downloaded to the user's computer and is not persisted on the server. The main application of POP3 (Post Office Protocol 3) in the POP protocol is the 3rd version of the Post Office Protocol. It is the protocol that specifies how personal computers connect to mail servers on the Internet to send and receive mail. It is the first offline protocol standard for Internet e-mail.

(3) IMAP (Internet Mail access Protocol), which is an interactive mail Access protocol,

It is a new protocol that is superior to pop. Like POP, IMAP can download messages, delete messages from the server, or ask for new messages, but IMAP overcomes some of the drawbacks of pop. There is no need to download the message locally, as the POP3 protocol does, and the messages and status of IMAP are consistent regardless of whether they are from a Web mailbox or a client mailbox.

In addition, there are some evolving protocols:

The IMAPS,SMTP protocol is based on a variant protocol on the SSL security protocol, which inherits the high security reliability of asymmetric encryption of SSL security protocol, which can prevent the message from being leaked.

There is a picture on the net, look at:

in my Foxmail is mainly used in the IMAP Agreement, SMT P agreement.

< Span style= "font-size:18px" >   protocol Port

< Span style= "font-size:18px" > receive P lang= "en-US" style= "margin:0in; Font-family:calibri; Font-size:10.5pt "> IMAP < strong>143 Port

Hair Smtp - Port

The 143 port is open for IMAP (Internetmessage ACCESS PROTOCOL) services and is used to receive messages.

- Port is SMTP ( simplemail Transfer Protocol , the Simple Mail Transfer Protocol) service is open for sending messages. When you send a message to someone, a dynamic port (greater than 1024x768) on your machine establishes a connection tothe mail server's port number. The messages you send will be sent to the mail server via this connection and saved.

	protocol	Port
Inbox	IMAP SSL	993 Port
Hair	SMTP SSL	- Port

993 port is for imaps ( imap-over-ssl ) protocol service open, used to receive mail , ratio IMAP is more secure

465 port ( smtps ): 465 port is for smtps ( smtp-over-ssl smtp more security.

Summary:

Through the different protocols and port protocols, we have different ways of handling mail, in order to facilitate I think the IMAP method is very simple.

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

Mail protocols and Ports