What is the difference between pop and smtp?


EQ Forum Admin
Staff member
SMTP, simple mail transfer protocol, typically running on port 25, is a protocol used by mail servers and programs to send and receive email.

POP, post office protocol, typically running on port 110, is a protocol used by email users to get access to the email stored on their mail servers.

In the real world an email will a follow a path such as :

  1. User sends email using SMTP to their outgoing mail server
  2. That outgoing mail server relays the email using smtp through one or more mail servers
  3. The destination mail server receives the email using SMTP
  4. The destination user retrieves their email from that server using POP
These days there are far more moving parts including virus, spam, and reputation filtering on one or more of the mail servers.