question about envelop from.

Im reading through rfc's but the following is still not clear for me.
E-mail is rejected base on the envelop-from adres from a mail-daemon with postfix + postfix-policyd-spf
I saw the following in the postfix logs.
Feb  7 00:00:16 hostname postfix/smtpd[31726]: Untrusted TLS connection established from[]: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)
Feb  7 00:00:16 hostname postfix/policy-spf[31766]: Policy action=PREPEND Received-SPF: none (apmcsqa01.poort: No applicable sender policy available); identity=mailfrom; envelope-from="MAILER- ... at apmcsqa01 dot poort";;]
Feb  7 00:00:16 hostname postfix/smtpd[31726]: NOQUEUE: reject: RCPT from[]]: 450 4.1.8 <MAILER- ... at apmcsqa01 dot poort>: Sender address rejected: Domain not found; from=<MAILER- ... at apmcsqa01 dot poort>
about this:
envelope-from="MAILER- ... at apmcsqa01 dot poort"
Im looking for the correct rfc where its described that the part @apmcsqa01.poort  should be @thesendingdomain.tld
where thesendingdomain.tld is also a resolvable domain, because not it does not make sence because the now mailer-daemon wil never be accepted because its non resolveable
If some can point me to the correct rfc. ( and chapter ) that would be great.


RE: question about envelop from.

By =?windows-1252?... at 03/13/2018 - 09:13

Hai Matus,
Thank you for the reply, most apriciated.

No, but its a "government" server, so i need to be very sure.. ;-)
Thanks, i was looking in the wrong rfc.

Best regards,


Re: question about envelop from.

By Matus UHLAR - f... at 03/13/2018 - 09:05

On 13.03.18 13:54, L.P.H. van Belle wrote:
who and why configured non-existing domain name there?

RFC 5321, section 2.3.5. Domain Names:

Only resolvable, fully-qualified domain names (FQDNs) are permitted
when domain names are used in SMTP.

correct. that is the expected behaviour.
do you expect someone to accept mail from non-existing (invalid) addresses?