Wietse Venema:
> Jaroslav Skarvada:
> > Hi,
> >
> > the postconf(5) documentation for reject_invalid_helo_hostname reads:
> > > Reject the request when the HELO or EHLO hostname syntax is invalid.
> >
> > This seems ambiguous as it can be interpreted different ways:
> > 1) 'HELO hostname' / 'EHLO hostname' syntax, i.e. HELO / EHLO syntax
> > 2) hostname syntax for HELO / EHLO
>
> SMTP syntax is specified in RFC 5321. If the client sends HELO,
> EHLO, MAIL or RCPT without a required command parameter, then that
> is an SMTP syntax error. The SMTP syntax error reply code is 501
> as specified in RFC 5321.
>
> Hostname syntax is specified in RFC 952 and 1123. If the client
> specifies an invalid name in HELO or EHLO, then that name may be
> rejected with reject_invalid_helo_hostname. This has a configurable
> reply code, like other like other main.cf reject_mumble actions for
> HELO, EHLO, MAIL, RCPT, etc., commands.
Updated text:
Reject the request when the HELO or EHLO command specifies a
malformed hostname.
There is no such thing as an "empty" HELO or EHLO parameter value
(there is no support for <> brackets at this protocol stage).
Wietse
