[GRLUG] Postfix HELO issue

[Grand Rapids Linux Users Group]

Yes, many, but not all, SMTP servers require a fully valid hostname, with
domain, in the HELO.

Often then will do a lookup on it in DNS to make sure it is real/exists as
well. Some even insist that the IP they get match the IP that the SMTP
connection is from.




On Thu, Aug 5, 2021 at 3:36 PM Grand Rapids Linux Users Group <
grlug at grlug.org> wrote:

> On Thu, 5 Aug 2021, Grand Rapids Linux Users Group wrote:
>
> > What is your sender SMTP sending as for HELO ?
> >
> > "fully qualified" means the receiver is expecting a full host and domain
> > name.
> >
> Ahh, .. same error on the receiving MTA:
>
> connect from majordomo.mailman.dd.org[24.38.28.134]
> Aug  5 13:14:10 mx2 postfix/smtpd[13410]: NOQUEUE: reject: RCPT from
> majordomo.mailman.dd.org[24.38.28.134]: 504 <majordomo>: Helo command
> rejected: need fully-qualified hostname; from=<postorius at mailman.dd.org>
> to=<lvl at omnitec.net> proto=ESMTP helo=<majordomo>
> Aug  5 13:14:10 mx2 postfix/smtpd[13410]: disconnect from
> majordomo.mailman.dd.org[24.38.28.134]
>
> Have never used a subdomain before, ... but that is what they wanted.
>
>         Thanks!!
> --
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> grlug at grlug.org
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>
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