[Info-vax] bizarre SMTP problem

[David J Dachtera]

Steven Underwood wrote:
> 
> "Bob Eager" <rde42 at spamcop.net> wrote in message
> news:176uZD2KcidF-pn2-PXhqF33pn2BN at rikki.tavi.co.uk...
> > On Thu, 9 Apr 2009 19:57:15 UTC, JF Mezei
> > <jfmezei.spamnot at vaxination.ca> wrote:
> >
> >
> > Then it appears to be a bug, since '+' is perfectly valid as a character
> > in an email address, as per RFC 2822 section 3.4.1.
> > --
> > Bob Eager
> >
> 
> That may be, but there are lots of systems that do not honor plussed
> addressing.  My mail provider (SpamCop.net) allows for plussed addressing
> but many web based systems find those addresses to be illegally formatted.

Such characters are not valid in UN*X usernames for many flavors of
UN*X, nor would it be allowed on VMS. So, it seems likely that an
attempt to verify the existence of such a user on a VMS or UN*X
receiving end would be likely to fail.

The protocol itself my not disallow it, but is that a valid username on
the receiving system, and if so, how is that validated?

D.J.D.