SMTP is a protocol for the transmission ofMail. Unlike standard POP3, this server is oriented mainly to the transfer, although it is possible to receive a letter to a certain address within the protocol.
SMTP is widely used by most modern mail services.
SMTP is implemented in modern standard networksTCP / IP. For the first time information about the use of the protocol appeared in 1982. Although the SMTP server can be used for receiving messages, today most mail clients use it only for sending, preferring other technologies (for example, POP or IMAP) to receive Information. The protocol is one of the most popular and is used by an overwhelming number of mail programs and servers.
The function of SMTP is to verify the correctnessSpecify settings and settings for sending a message. The protocol verifies the settings of the user's computer trying to send messages, and then the delivery is performed, if all the settings were performed correctly. After that, the SMTP operation does not end and the server waits for a message about the successful delivery of the data. If the message can not be delivered for some reason, a corresponding message is sent to the sender.
Configuring SMTP is to install the requiredSoftware and determine the address of the server used for sending. For sending by the user, it is required to install a client program that can send messages and communicate with the SMTP server via TCP / IP. After that, the program is launched and configured to work with the service to send and receive mail by specifying the desired settings. Then the user tries to send a message. If the setting is correct, the message will be delivered to the recipient.
Most modern e-servicesMail already has customized servers for sending messages. If you do not use third-party software to send letters, you can send a message without making any additional settings on the site of the service where you have an account registered.
Modern administrators of SMTP-servers requireFrom users of authentication before they can send their messages. The user must first specify his login and password on the server, and only then go to the shipment. This protection is used to block the possibility of sending spam using simple SMTP protocols. Previously, the unique IP-address of the sender was used for identification in the SMTP protocol.