POP and Spam last modified

Email set up with POP does not filter spam or report spam to the upstream mail server.

Following is a technical summary of that statement based on the POP protocol definition, RFC 1939.

RFC 1939 does not specifically mention commands for passing spam information between customer devices and servers. Here are a few points about RFC 1939 and spam:

  1. RFC 1939 predates the widespread problem of email spam. It was published in 1996, before spam became a major issue plaguing email.

  2. The core focus of RFC 1939 is defining POP3, a protocol for downloading email from a server. It does not deal with spam filtering or reporting.

  3. However, RFC 1939 does allow for optional POP3 service extensions. So later RFCs could potentially define spam reporting extensions.

  4. There are other RFCs and protocols such as IMAP (RFC 3501) focused on fighting spam. RFC 2505 defines anti-spam extensions for SMTP, enabling communication of spam reports between mail servers.

  5. Modern email applications and servers have much more sophisticated spam detection and filtering capabilities compared to what was available in 1996. Machine learning techniques can identify spam with high accuracy today.

In summary, RFC 1939 itself does not define spam reporting functionality, but later protocols such as IMAP build on top of RFC 1939 to add spam fighting capabilities to email. The problem of spam was not a major consideration in the original design of POP3.

The POP protocol, RFC 1939, may be found at RFC 1939

The IMAP protocol, RFC 3501, may be found at RFC 3501