RFC 491 (rfc491) - Page 1 of 2
What is "Free"?
Alternative Format: Original Text Document
Network Working Group M. A. Padlipsky
Request for Comments: 491 MIT-Multics
NIC: 15356 12 April 1973
What Is Free
In at least three of the RFC's about "mail" and the File Transfer
Protocol (RFC's 454, 475, 479), something very like the following is
asserted: "Network mail should be free; i.e., no login or USER
command should be required." Unfortunately, "i.e" (=that is) is
misleading. It simply does not follow to imply that the only way
mail can be free is for it not to require a login; explicit login on
a free account would of course also work. Indeed, depending upon
per-Host idiosyncrasies in the Logger / Answering Service / process
creation environment, an explicit login may well prove to be far more
natural than an implicit login. (Even in environments where implicit
login is easy, surely explicit login is just easy.) Granted, login
on a free account requires users to remember the name of the free
account. However, this would not be too great a burden to bear if
there were reasons for preferring an explicit login and if the free
account had the same name on all Hosts. Therefore, from the promise
that Network protocols should not implicitly legislate "unnatural"
implementations for participating Hosts if it is conveniently
avoidable, I propose the following formulation:
Network mail should be free. Network mail should not require
users to remember the name of the free account on a given system.
I.e., it should either be "loginless" or it should take the same
login everywhere. But some systems need/want/prefer a login.
Therefore, USER NETML / PASS NETML should be made to work
everywhere for free mail.
Note: "NETML" is fewer than six characters and is upper case
hence, it should fit in the least common denominator category
of user identifiers, but it's still long enough not to conflict
with anybody's initials (in all probability).
Now, because of the implementation implications this may all sound
like special pleading, but I claim that another implication of the
"incorrect" formulation will further show the superiority of an
explicit login for mail. For the "loginless" view leads to problems
in regard to the authentication aspects of login and the accounting
aspects, by apparently assuming that the sole purpose of login is to
initiate accounting. In RFC 475, the problem is exposed when, after
noting that some systems allow access control to be applied to
mailboxes, it is asserted that FTP USER command is wrong for access
control because you'd then be on the free account and a new FTP FROM
Padlipsky