He said "above TCP". > it eliminates mail and news forgery above TCP I have some trouble guessing offhand what flavor of security confusion was fresh in mind

He said "above TCP". > it eliminates mail and news forgery above TCP I have some trouble guessing offhand what flavor of security confusion was fresh in mind from the preceding 3 to 10 years (and I was yet to be born), but after glancing at RFC 931, I'm going to guess that before this, user-hostname identifiers were handled in varied ad-hoc ways allowing spoofing of sender, or connecting user. I'm careful not to say "authenticating" user. https://datatracker.ietf.org/doc/html/rfc931 https://datatracker.ietf.org/doc/html/rfc931 It's actually an evergreen problem, happened on a new social site, last week. A message from your good friend, Amazon S3: https://pbs.twimg.com/media/FvW7NJtWAAAocCe?format=jpg&name=small https://pbs.twimg.com/media/FvW7NJtWAAAocCe?format=jpg&name=...