> Date: Thursday, January 21, 2021 15:24:10 +0100
> From: "Herbert J. Skuhra" <herb...@gojira.at>
>
> On Thu, Jan 21, 2021 at 03:15:24PM +0100, Jeff Abrahamson wrote:
>> I've been seeing this error for this one host. My first reaction
>> was that the host was incorrectly configured, but the IP
>> (92.103.176.37) reverse resolves to mail.mairie-carquefou.fr,
>> which in turn resolves to that IP. In addition, the MX for
>> mairie-carquefou.fr is mail.mairie-carquefou.fr (and
>> mx3.mail.ovh.net). So I'm not really sure what the "host not
>> found" is complaining about.
>>
>> Jan 21 15:05:28 nantes-1 postfix/smtpd[6367]: connect from
>> mail.mairie-carquefou.fr[92.103.176.37]
>> Jan 21 15:05:29 nantes-1 postfix/smtpd[6367]: Anonymous TLS
>> connection established from
>> mail.mairie-carquefou.fr[92.103.176.37]: TLSv1 with cipher
>> ECDHE-RSA-AES256-SHA (256/256 bits)
>> Jan 21 15:05:29 nantes-1 postfix/smtpd[6367]: NOQUEUE: reject:
>> RCPT from mail.mairie-carquefou.fr[92.103.176.37]: 450 4.7.1
>> <SERVDMZMAIL.mairie-carquefou.fr>: Helo command rejected: Host not
>> found; from=<direction.gener...@mairie-carquefou.fr>
>> to=<x...@transport-nantes.com> proto=ESMTP
>> helo=<SERVDMZMAIL.mairie-carquefou.fr>
>> Jan 21 15:05:29 nantes-1 postfix/smtpd[6367]: disconnect from
>> mail.mairie-carquefou.fr[92.103.176.37] ehlo=2 starttls=1 mail=1
>> rcpt=0/1 quit=1 commands=5/6
>>
>> (I'm a bit confused about the SERVDMZMAIL in the helo. That host
>> does appear not to exist.)
>>
>> Any suggestions what to look at / if I've likely misconfigured
>> something?
>
> http://www.postfix.org/postconf.5.html#smtpd_helo_restrictions
>
> reject_unknown_helo_hostname (with Postfix < 2.3:
> reject_unknown_hostname) Reject the request when the HELO or
> EHLO hostname has no DNS A or MX record.
... and your HELO is from:
450 4.7.1 <SERVDMZMAIL.mairie-carquefou.fr>:
Helo command rejected: Host not found;
which doesn't appear to resolve.
