What is the difference between Port 465 and port 587?
What is the difference between Port 465 and port 587?
Port 587 has always been the default port for message submission. The confusion around port 465 and port 587 stems back to 1997 when a standard for encrypted transit was being discussed. Ultimately, StartTLS was the protocol chosen. This enables a user to send with plaintext, or upgrade their connection to TLS using the same port.
What is SMTP port 587 used for?
During the same year, the IETF standardized StartTLS on port 587 as the encryption protocol for SMTP message submission. In an effort to simplify the process of encrypting SMTP messages, port 465 and smtps, were removed from the IANA registry.
What is port 465 used for?
To remedy this, the IETF issued a one-time amendment to reinstate port 465 for message submission over TLS protocol. Today, port 465 is still listed on the IANA registry as the service port for message submission and URL Rendezvous Directory for SSM, URD for short.
Can dynamic ports be used without registration?
Dynamic Ports are not assigned. The registration procedures for service names and port numbers are described in . Assigned ports both System and User ports SHOULD NOT be used without or prior to IANA registration.
How are system ports assigned to IANA?
According to Section 8.1.2 of [ RFC6335 ], System Ports are assigned by the “IETF Review” or “IESG Approval” procedures described in [ RFC8126 ]. User Ports are assigned by IANA using the “IETF Review” process, the “IESG Approval” process, or the “Expert Review” process, as per [ RFC6335 ].
Is it safe to send email over Port 465?
However, many ESPs have adopted implicit TLS on port 465. While you can send email over port 25 and 2525, it’s much more secure to have the messages encrypted. This makes port 587 the preferred option for sending, with port 465 as a close second.
How are serviceservice names and port numbers assigned?
Service names are assigned on a first-come, first-served process, as documented in [RFC6335]. Port numbers are assigned in various ways, based on three ranges: System Ports (0-1023), User Ports (1024-49151), and the Dynamic and/or Private Ports (49152-65535); the difference uses of these ranges is described in [RFC6335].
