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List:       postfix-users
Subject:    Re: hostname net6-ip74.linkbg.com does not resolve
From:       Viktor Dukhovni <postfix-users () dukhovni ! org>
Date:       2020-05-29 0:48:23
Message-ID: 20200529004823.GI48101 () straasha ! imrryr ! org
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On Fri, May 29, 2020 at 01:11:08AM +0200, maurizio@caloro.ch wrote:

> I am not shure if this are normal? In my postfix log this message appair now
> 2 days.
> 
> May 29 00:59:22 mail postfix/smtpd[12989]: warning: hostname
> net6-ip74.linkbg.com does not resolve to address 87.246.7.74: Name or
> service not known

The host in question does not exist (NXDOMAIN) in the forward DNS zone
of linkbg.com.

> May 29 00:59:43 mail postfix/smtpd[12781]: warning: hostname
> net6-ip70.linkbg.com does not resolve to address 87.246.7.70: Name or
> service not known

You're getting SMTP connections 87.246.7.70 (et. al.) which claim to be
have names like net6-ip70.linkbg.com:

    $ dig +noall +ans +nocl +nottl -x 87.246.7.70
    70.7.246.87.in-addr.arpa. CNAME	70.0-255.7.246.87.in-addr.arpa.
    70.0-255.7.246.87.in-addr.arpa.	PTR net6-ip70.linkbg.com.

However that name is fiction:

    $ dig +noall +noedns +comment -t a net6-ip70.linkbg.com.
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 13194
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

> Thanks for any possible Update

Postfix logs the fact that the name is fiction.  That's all.
Nothing to worry about.

-- 
    Viktor.
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