POP3before is one method used for the sending and receiving of mail.
A mail server uses two types of protocol to send and receive mail. Generally when mail is sent it uses an SMTP server and when receiving mail uses a POP server.
Normally, the sending and receiving of mail are done separately. However, recently in an effort to fight Spam mail a new type of mail server, referred to as POP3before, has been developed.
The way it works is that after logging in with your Login ID and password to the POP server you can then have access to the SMTP server for a certain length of time in order to send mail.
RTR-500 Series, TR-700W Series, TR-71W/72W, WDR-3, WS-2
September 08, 2016