On Mon, May 17, 1999 at 09:19:29AM -0400, Eric Shafto wrote:
> > > > (I'm considering changing the default HELO in qmail-remote in qmail 2.0
> > > > to use the bracketed IP address of the client.)
> > >
> > > How much of a standard is that?
> >
> > RFC821:
> >
> > HELO <SP> <domain> <CRLF>
> > <domain> ::= <element> | <element> "." <domain>
> > <element> ::= <name> | "#" <number> | "[" <dotnum> "]"
> > <dotnum> ::= <snum> "." <snum> "." <snum> "." <snum>
> > <snum> ::= one, two, or three digits representing a decimal
> > integer value in the range 0 through 255
> >
> > Therefore,
> >
> > HELO [199.103.176.41]
>
> But so does:
>
> HELO [199.103.176.41].#394875.spoon.[100.164.68.209]
I don't think so. None of the above elements (the bracketed IPs, "spoon"
and "#394875") are of class "snum". Therefore the above HELO is not valid.
However, RFC 1123 5.2.5 states clearly that no smtp server must refuse mail
even if the domain in the HELO greeting is invalid. So in theory, you
should be able to say HELO <anything> to an SMTP server, and it would have
to accept your email. In practice, many SMTP servers reject such a
connection.
--
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