Re: Bluewin Error: Der MX-Eintrag fuer die Domaene aerni.com kann nicht verifiziert werden

<[email protected]> Fri, 12 Jan 2018 11:12:53 +0000

Newsgroups	gmane.org.operators.swinog
Message-ID	<[email protected]>

Hello Benoît

Put simply, we do DNS requests for MX or A records for the given sender domain, if either exists this check is passed.

As for the issue at hand: the DNS servers of your customer are (were) not properly reachable from our IP ranges or more specifically we are (were) unable to get the IPs for ns1.aerni.com or ns2.aerni.com. During our investigation this resolution has mostly recovered and we are able to resolve the domain properly, so this issue should now be resolved. This makes it harder though to pinpoint the exact cause here, to us it currently seems though that NS records have been changed and the old DNS servers been turned off before the TTLs of the old NS records had expired, so some intermediate DNS/CNS servers still had cached info that was now no longer working and this made the domain unresolvable to our servers.

As a side note: both NS entries now share a single IP and that is even the same IP as the mail server, this is definitely not an optimal setup, an offsite secondary DNS server that didn't need changing might have prevented this from the start.

Regards
Marcel

-----Ursprüngliche Nachricht-----
Von: [email protected] [mailto:[email protected]] Im Auftrag von Benoit Panizzon
Gesendet: Freitag, 12. Januar 2018 10:31
An: [email protected]
Betreff: [swinog] Bluewin Error: Der MX-Eintrag fuer die Domaene aerni.com kann nicht verifiziert werden

Hello List

Does anyone know, how bluewin does 'verify' an MX?

The MX of our customer is prefectly reachable for sender verification but his emails sent 'to' bluewin recipients are getting blocked with:

MAIL FROM: <[scrubbed]@aerni.com> Unable to verify MX-Record for domain aerni.com

aerni.com mail is handled by 10 mail.aerni.com.

mail.aerni.com has address 87.102.181.130

Connected to mail.aerni.com.
Escape character is '^]'.
220 mail.aerni.com ESMTP ready.
quit
221 mail.aerni.com closing connection
Connection closed by foreign host.
benoit@krup:~$ telnet mail.aerni.com. smtp Trying 87.102.181.130...
Connected to mail.aerni.com.
Escape character is '^]'.
220 mail.aerni.com ESMTP ready.
ehlo imp.ch
250-mail.aerni.com Hello dhcp-186.imp.ch [157.161.4.186] 250-SIZE 52428800 250-8BITMIME 250-PIPELINING 250-AUTH PLAIN LOGIN 250-STARTTLS
250 HELP
mail from:<>
250 OK
rcpt to:<[scrubbed]@aerni.com>
250 Accepted
rset
250 Reset OK

Mit freundlichen Grüssen

-Benoît Panizzon-
--
I m p r o W a r e A G - Leiter Commerce Kunden
______________________________________________________

Zurlindenstrasse 29 Tel +41 61 826 93 00
CH-4133 Pratteln Fax +41 61 826 93 01
Schweiz Web http://www.imp.ch
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