Forwarding hosts in mail addresses

[David Vinayak Wallace <Gumby@MCC.COM>]

    Date: Mon, 24 Apr 89 14:55:17 EDT
    From: MILLER@vax.cam.nbs.gov

    Apparently a number of mailers will accept the following syntax:
      @FORWARDING_HOST:USER_NAME@HOST.DOMAIN
    meaning that you want to send mail to USER_NAME@HOST.DOMAIN
    but send it via FORWARDING_HOST.  The point presumably being
    that the local host doesnt know about HOST (ie doesnt have
    the full domain service running), but FORWARDING_HOST will 
    be able to figure it out. 

    This works on suns and even the EXLAN mailer on vax/vms
    (with a little syntactic sugar).  However, the LM chokes on 
    the initial `@'.   Does anybody know how to make this work,
    or an alternate syntax?

RFC822 requires angle brackets around a route-addr (eg, <@FORWARDING_HOST:UNAME@DOMAIN>)
See section 6.1.  If it works on other machines that's not because
they're correct (although the standard says "be liberal in what you
accept and conservative in what you send out").

It's a shame you have to use this kludge.  That's not what it was
intended for.  But the %-hack only works because some mailers (not
including Symbolics') choose to implement it -- not because it's part of
a standard.