Post Office Protocol 3 (POP3) is the third most primary version of a way to receive emails. Mimicking a real post office clerk, POP3 receives and stores emails or a user until they retrieve them.

POP3, as the third version, has an additional function of copying the retrieved email for storage and archival purposes to be stored for a specified period of time. This function is performed at the behest of certain system administrators.

This allows them to download any stored email an unlimited amount of times in a previously defined period of time. This method is not the most practical though for the simple majority of email users. Although there have been many alternatives to POP3, such as IMAP, POP3 remains the highest rated service due to its ease of use and high success rate.

Despite the more recent versions of POP that sell by offering more features, POP3 is still mostly preferred because it gets the job done with the least amount of errors. POP3 can work with basically any email program as long as the email program is likewise configured to accept and host POP3.

Most of the popular alternatives such as Microsoft Outlook or Eudora are intentionally designed to automatically accept and host POP3. Every POP3 email server has a different address, which generally is provided to a user by their web hosting company.

Generally speaking, the majority of email applications use the 110 port to connect to POP3. Those users who are configuring an email program to receive POP3 email would also need to input their user names and passwords in order to safely receive their messages.