They have a swathe of issues on those IP's, not just reverse. Here is a
snippet of an email header from an email received on my systems:
Received: from SY4AUS01FT010.eop-AUS01.prod.protection.outlook.com
(2603:10c6:10:0:cafe::45) by SYBPR01CA0024.outlook.office365.com
(2603:10c6:10::36) with Microsoft SMTP Server (version=TLS1_2,
cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4173.22 via Frontend
Transport; Tue, 1 Jun 2021 00:35:55 +0000
X-MS-Exchange-Authentication-Results: spf=fail (sender IP is 139.130.208.5)
smtp.mailfrom=<domain name>; <domain name>; dkim=none (message not
signed) header.d=none;<domain name; dmarc=none action=none
header.from=<domain name>;
SPF failures within their systems and they have also found their way
onto the barracuda RBL for some IP's, specifically 40.92.63.28
Regards
Gavin Roche..
On 11/6/21 9:57 am, Mal wrote:
Last couple days for sure... but has been going longer with
40.92.62-63.0/24 for a couple weeks
Which for any decent postfix MTA configuration will cause a 554.
>
Jun 10 09:20:20 cust-mta01 postfix/smtpd[8137]: NOQUEUE: reject: RCPT
from unknown[40.92.62.80]: 554 5.7.1 Client host rejected: cannot find
your reverse hostname, [40.92.62.80]; from=<[email protected]>
to=<[email protected]> proto=ESMTP
helo=<AUS01-SY4-obe.outbound.protection.outlook.com>
Mal
On 11/06/2021 8:47 am, Mike Manning wrote:
Hi all,
Anyone else here experiencing missing RDNS for a swath of IP’s from
Microsoft on a few different subnets? I’ve opened a ticket with
Microsoft netops for it and I’ve done an rDNS bypass on our local
antispam filter however we’re now seeing o365 clients with the same
issue when trying to receive emails from anyone with an @outlook.com
or @msn.com email address.. where do you draw the line in adding
bypass after bypass?
host 40.92.63.85
Host 85.63.92.40.in-addr.arpa. not found: 3(NXDOMAIN)
host 40.92.62.31
Host 31.62.92.40.in-addr.arpa. not found: 3(NXDOMAIN)
*Mike Manning*
*Network Engineer*
*Matilda Internet*
________________
(Telephone +61 7 4953 0711
(Fax +61 7 4849 5000
29 Gregory Street, Mackay, QLD 4740, Australia
*[email protected]
<mailto:[email protected]>Websitewww.matilda.net.au
<http://www.matilda.net.au/>
This email and any files transmitted with it are confidential and are
intended solely for the use of the individual or entity to whom it is
addressed. If you are not the recipient be advised that you have
received this email in error and that any use, dissemination,
forwarding, printing copying or use of the contents contained in this
e-mail and any file attachments is strictly prohibited. If you have
received this email in error please immediately notify the sender by
telephone or by reply email to the sender. You must destroy the
original transmission and its contents. It is recommended that you
virus test the information and any attachments. Matilda Internet
does not accept liability for any loss or damage howsoever occurred
as a result of this email transmission or any attachments to it.
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