Violation Type:Outgoing Port 25 Blocking
|BT Broadband/NPORTOUT25||BT Broadband|
|Google Compute Engine/NPORTOUT25||Google Compute Engine|
See NPORTOUT. Blocking of port TCP/25 outgoing is particularly common as an anti-spam measure. Nonetheless, this is a net neutrality violation.
The blocking of port 25 outgoing is interesting as it is a case of the IETF being apparently complicit in an initiative the sole utility of which is to facilitate net neutrality violations: the introduction of port 587 as the SUBMISSION port has essentially zero utility but to facilitate discrimination between MTA-to-MTA communciations and MSA-to-MTA communications, and thereby make the blocking of port 25 outgoing for certain classes of internet connections palatable.