Helo command rejected: Host not found;

[Josef Sturm]

An Australian Government site is trying to send me a (confirmation) email, but my mail server (set up and run by myself) rejects the incoming email.

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Nov 8 05:26:24 mail1 postfix/postscreen[1685596]: CONNECT from [103.151.87.18]:60820 to [xxx.xxx.xxx.xxx]:25
Nov 8 05:26:24 mail1 postfix/postscreen[1685596]: PASS OLD [103.151.87.18]:60820
Nov 8 05:26:28 mail1 postfix/smtpd[1685599]: connect from s2bulkseg.ato.gov.au[103.151.87.18]
Nov 8 05:26:31 mail1 postfix/smtpd[1685599]: NOQUEUE: reject: RCPT from s2bulkseg.ato.gov.au[103.151.87.18]: 450 4.7.1 <s2-smtp-ato-esa32.secureintellicentre.net.au>: Helo command rejected: Host not found; from=<***@mygovid.gov.au> to=<***@xxx.com> proto=ESMTP helo=<s2-smtp-ato-esa32.secureintellicentre.net.au>
Nov 8 05:26:36 mail1 postfix/smtpd[1685599]: disconnect from s2bulkseg.ato.gov.au[103.151.87.18] ehlo=2 starttls=1 mail=1 rcpt=0/1 rset=1 quit=1 commands=6/7
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Appreciate if somebody could tell me if this may be due to something I've set up incorrectly.
All other mails to my domain come through
Thanks

[Bob Nichols]

Post by Josef Sturm
An Australian Government site is trying to send me a (confirmation) email, but my mail server (set up and run by myself) rejects the incoming email.
---------
Nov 8 05:26:24 mail1 postfix/postscreen[1685596]: CONNECT from [103.151.87.18]:60820 to [xxx.xxx.xxx.xxx]:25
Nov 8 05:26:24 mail1 postfix/postscreen[1685596]: PASS OLD [103.151.87.18]:60820
Nov 8 05:26:28 mail1 postfix/smtpd[1685599]: connect from s2bulkseg.ato.gov.au[103.151.87.18]
Nov 8 05:26:36 mail1 postfix/smtpd[1685599]: disconnect from s2bulkseg.ato.gov.au[103.151.87.18] ehlo=2 starttls=1 mail=1 rcpt=0/1 rset=1 quit=1 commands=6/7
---------
Appreciate if somebody could tell me if this may be due to something I've set up incorrectly.
All other mails to my domain come through
Thanks

There is no DNS "A" record set up for the hostname
"s2-smtp-ato-esa32.secureintellicentre.net.au", reported in the
HELO/EHLO command from the sending server. Such a message would
be deferred in this way if "smtpd_helo_restrictions" includes
"reject_unknown_helo_hostname".

If that is not the case, please post your main.cf configuration.