You _really_ need to read and understand the ABNF in these specifications.
All of your questions can be answered simply by reading the ABNF.
To get you started in how to use the ABNF, I'll answer your questions:
--On Wednesday, August 15, 2001 19:14 -0700 Lee Thompson
<lt(_at_)seattlelab(_dot_)com> wrote:
1. Are quotes taken as literal delimiters in comments? E.g.
Joe(A comment ")" here)User(_at_)arrgh(_dot_)org
No. See the ABNF in RFC 2822. Note that a double-quote is part of "ctext"
which is part of "ccontent".
2. Is there such a thing as a comment in a literal such that the comment
gets stripped?
"Joe(The Thug) User"@arrgh.org
No. See the ABNF in RFC 2822. Parens are part of "qtext".
3. Should comments be omitted in any 821/2821 envelope?
Yes. See ABNF for "Mailbox" in RFC 2821. No comments permitted in there.
Is it better
just to pass through quoted stuff completely untouched?
Yes.
Should a quote
char '\' be stripped out when found - or just passed on?
Within a quoted string, I'd leave quoted-pairs alone (indeed if it quotes
'\' or '"', you have to leave it alone or you're breaking the address).
Outside the quoted string, it depends. If you're claiming conformance with
RFC 2821 you'd have to reject the address or strip it (since it's a
protocol syntax violation to generate a quoted pair outside of a quoted
string when acting in the SMTP client role). If you're only claiming
conformance with RFC 821, you could pass it on.
4. We've run into a particular MTA that does not escape commas in quoted
local-parts which appear to be contrary to at least RFC 2822. E.g.
"8379,39082"@domain.com It seems prudent to accept this as is and
continue on.
That is a perfectly legal and correct address by RFC 2822 since "," is in
qtext.
- Chris