Path: utzoo!yunexus!geac!syntron!jtsv16!uunet!lll-winken!lll-tis!ames!think!bloom-beacon!mit-eddie!rutgers!elbereth.rutgers.edu!ron.rutgers.edu!ron
From: ron@ron.rutgers.edu (Ron Natalie)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Internet Mail Addressing Question !!
Message-ID: <Oct.24.11.30.28.1988.12173@ron.rutgers.edu>
Date: 24 Oct 88 15:30:30 GMT
Article-I.D.: ron.Oct.24.11.30.28.1988.12173
References: <8810240122.AA18599@FORD-COS2.ARPA>
Organization: Rutgers Univ., New Brunswick, N.J.
Lines: 21

RFC 822 and SMTP and Internet mail in general doesn't know '%' from
any other character.  When you send mail there are essentially two
significant parts.  The stuff to the left of the '@' and the stuff
to the right of the '@'.  When you send mail to a remote machine
you interpret the stuff to the right as the machine to connect to and
pass to it the stuff on the left uninterpretted.

Now if a host wants to use this character for some internal use (either
it allows a mailbox name to contain that character, or it is used for
a separater), this makes no difference to SMTP or 822.  All it knows
is that you care dropping mail into a mailbox whose id is the stuff
to the left of the '@.'

Now some machines use % as a special separator (notably older attempts
at CSNET mail).  They will essentially throw away the '@' and what is
to the right and then turn the % into an '@' and attempt to resend the
mail.  Generally this was used to route mail to another host which is
not really on the newtork.  However, it is up to the recipient host to
make this distinction, and if a host decided that % in a name means to
send that mail to the lineprinter, it's free to make that interpretation.

-Ron