Path: ...!weretis.net!feeder9.news.weretis.net!tncsrv06.tnetconsulting.net!tncsrv09.home.tnetconsulting.net!.POSTED.omega.home.tnetconsulting.net!not-for-mail
From: Grant Taylor <gtaylor@tnetconsulting.net>
Newsgroups: comp.mail.sendmail
Subject: Re: reject=553 5.3.0 127.0.0.2 due to unreachable DNS resolver
Date: Sun, 2 Feb 2025 16:42:16 -0600
Organization: TNet Consulting
Message-ID: <vnosc8$ano$1@tncsrv09.home.tnetconsulting.net>
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On 2/2/25 14:11, Marco Moock wrote:
> That error is fine, but in my case it was 553 and I would like to 
> understand what caused that.

I'll try saying it another way, my -- limited -- understanding is that 
the `454 4.7.1 Listed in ...' error is only sent when there DNS timeout 
/ failures (multiple times).

I think that Sendmail will return a different (error) message when it 
successfully looks up the IP address and finds it listed in the 
(ENH)DNSBL.  I think it's entirely possible that the 553 was because the 
client's IP was listed in the (EHN)DNSBL.  The 553 even included the IP 
address from the listing.

But, as said before, I don't use (ENH)DNSBL and don't have any first 
hand experience with it.



-- 
Grant. . . .