[dfox]

I meant it in the confidentiality sense. The fact that you can put anything on the cover sheet and header line as sender number and that it has exactly zero relevance as authenticator should be obvious to anyone who actually ever set up a fax machine.

Edit: and exactly how that differs from SMTP?

[msla]

An office fax machine sitting out in the open is going to be less confidential than email on an SMTP server where only a sysadmin or the recipient can see it, yes.