Re: [Exim] EHLO advertising

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Author: Nigel Metheringham
Date:  
CC: exim-users
Subject: Re: [Exim] EHLO advertising
On Wed, 2002-11-20 at 12:52, Michael Jakscht wrote:
> Nigel Metheringham <Nigel.Metheringham@???> wrote on 20
> Nov 2002 12:48:20
>
> > Basically this is your primary_hostname setting.
> >
> > However the argument to a HELO is the name of the *host* you are
> > connecting from, not anything to do with MX values. Putting an MX name
> > in there is likely to cause more rejections rather than less.
>
>
> Okay, thans for this answer, but why would this setting reject more mails
> than less???
> Would be great if you could explain that... ;-)


Take an example.

example.com - that well known manufacturer of sample domain names - have
a mail system:-
    mail.example.com.    IN A 192.168.10.1


and some MX records
    example.com        IN MX 1 mail.example.com.


There are no other records in their forward DNS. The reverse has a ptr
record correctly linking 192.168.10.1 with mail.example.com.

On the mail machine, primary_hostname should be set to
"mail.example.com", and this value used in the HELO/EHLO lines, as well
as in the SMTP banner.

Putting something other than the hostname there (ie anything that does
not DNS resolve to an A record pointing to 192.168.10.1) is giving other
people grounds for rejecting you - *including* using "example.com"
within the HELO/EHLO lines.

    Nigel.
--
[ Nigel Metheringham           Nigel.Metheringham@??? ]
[ - Comments in this message are my own and not ITO opinion/policy - ]