POP is used for retrieving emails from a mail server. SMTP is used for sending emails to a mail server and sending emails between mail servers. If you'd like to learn more about POP and SMTP, take a look at these RFCs:
- RFC 1939 for POP, which you can see in the following screenshot (https://tools.ietf.org/html/rfc1939):
- RFC 2821 for SMTP, which you can see in the following screenshot (https://tools.ietf.org/html/rfc2821):
In the preceding screenshot, you'll see there are a number of commands that are transmitted between the ...
