Article ID: 3200, created on Nov 30, 2007, last review on May 10, 2014
POP before SMTP
An SMTP based protocol, in which the relay system collects IP addresses of users who successfully authenticate themselves with a POP server, and then permits SMTP relaying from that IP address for a short period of time.
An SMTP based protocol, in which the client must send a name and password in addition to the normal SMTP envelope information. This requires a special client, which has been configured to use this protocol.