Subject: unpleasant e-mail addresses

From: "Edmund GRIMLEY-EVANS" <[email-masked]>
Date: Thu, 09 Sep 1999 11:20:07 +0100

RFC 822 seems to allow some ghastly things like

From: x."@@".\.@a.[1 2 3].com

(Using quoted-strings in the local-part and domain-literals in the domain.)

Have these things ever been officially disallowed or discouraged?

Does c-client try to support them?

Is it guaranteed anywhere that different ways of quoting or escaping
are to be treated as equivalent, for example, that the following strings
specify the same mailbox?

To: \@@abc.edu
To: "@"@abc.edu

Or even:

To: \..".."@abc.edu
To: \.\.."."@abc.edu
To: "...."@abc.edu
...etc...

Edmund

---

From: Mark Crispin <[email-masked]>
Date: Thu, 9 Sep 1999 10:14:23 -0700 (PDT)

> From: x."@@".\.@a.[1 2 3].com

"a.[1 2 3].com" is not valid in the RFC 822 successor, nor has it ever been
valid as an Internet address.

> Have these things ever been officially disallowed or discouraged?

The RFC 822 successor abolishes mixing of domain literals with domains.  If a
domain literal appears, it must be the only part of the domain.

The RFC 822 successor specifically forbids unquoted spaces in the local part
and domain.  Some people misunderstood RFC 822's rules (and the note at the
bottom of page 8 of RFC 822) to content that spaces are allowed around "."
characters (trust me, I was there when RFC 822 was written and that note on
page 8 was written -- it was specifically intended that these not be allowed).
Domain literals are a type of quoting, thus spaces continue to be allowed
there.

This reflects what has been practical reality for many years.  It was never an
issue until a certain individual decided to waste people's time for over a
year arguing about it.

> Does c-client try to support them?

c-client is in compliance with the RFC 822 successor.  However, the fact that
c-client supports various bizarre addresses doesn't mean that you should
actually use them.

> are to be treated as equivalent

Yes