SMTP is a simple mail sending protocol. It can be understood as a data sending protocol, through which the data on your mail server is sent out.
The STMP servers of 126, 163 and QQ require authentication (that is, you need your account and password in their mailbox) to send emails through their STMP servers.
This only involves the sender and does not affect the recipient.
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
SMTP is a simple mail sending protocol. It can be understood as a data sending protocol, through which the data on your mail server is sent out.
The STMP servers of 126, 163 and QQ require authentication (that is, you need your account and password in their mailbox) to send emails through their STMP servers.
This only involves the sender and does not affect the recipient.
As long as the pop3 protocol is normal for receiving messages, smtp is only used when sending messages