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    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:<br>
    <br>
    <pre class="c-mrkdwn__pre" data-stringify-type="pre" style="box-sizing: inherit; margin: 4px 0px; padding: 8px; --saf-0:rgba(var(--sk_foreground_low,29,28,29),0.13); font-size: 12px; line-height: 1.50001; font-variant-ligatures: none; white-space: pre-wrap; overflow-wrap: break-word; word-break: normal; tab-size: 4; font-family: Monaco, Menlo, Consolas, "Courier New", monospace !important; border: 1px solid var(--saf-0); border-radius: 4px; background: rgba(var(--sk_foreground_min,29,28,29),0.04); counter-reset: list-0 0 list-1 0 list-2 0 list-3 0 list-4 0 list-5 0 list-6 0 list-7 0 list-8 0 list-9 0; color: rgb(29, 28, 29); font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">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>;</pre>
     <br>
    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<br>
    <br>
    <br>
    Regards<br>
    Gavin Roche..<br>
    <br>
    <br>
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    <div class="moz-cite-prefix">On 11/6/21 9:57 am, Mal wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:9f19f81e-0bb8-2aa4-14d5-6d273db5a180@jetlan.com">
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      Last couple days for sure...  but has been going longer with
      40.92.62-63.0/24 for a couple weeks<br>
      <br>
      Which for any decent postfix MTA configuration will cause a 554.<br>
      <br>
      ><br>
      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=<a
        class="moz-txt-link-rfc2396E" href="mailto:user@outlook.com"
        moz-do-not-send="true"><user@outlook.com></a> to=<a
        class="moz-txt-link-rfc2396E"
        href="mailto:customer@domain.com.au" moz-do-not-send="true"><customer@domain.com.au></a>
      proto=ESMTP
      helo=<AUS01-SY4-obe.outbound.protection.outlook.com><br>
      <br>
      Mal<br>
      <br>
      <br>
      <br>
      <br>
      <div class="moz-cite-prefix">On 11/06/2021 8:47 am, Mike Manning
        wrote:<br>
      </div>
      <blockquote type="cite"
cite="mid:5D207EB4DB92C34A86B2CA50AC286F4338C5CAB3@Exchange.matilda.net.au">
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          <p class="MsoNormal">Hi all,<o:p></o:p></p>
          <p class="MsoNormal"><o:p> </o:p></p>
          <p class="MsoNormal">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? <o:p></o:p></p>
          <p class="MsoNormal"><o:p> </o:p></p>
          <p class="MsoNormal">host 40.92.63.85<o:p></o:p></p>
          <p class="MsoNormal">Host 85.63.92.40.in-addr.arpa. not found:
            3(NXDOMAIN)<o:p></o:p></p>
          <p class="MsoNormal"><o:p> </o:p></p>
          <p class="MsoNormal">host 40.92.62.31<o:p></o:p></p>
          <p class="MsoNormal">Host 31.62.92.40.in-addr.arpa. not found:
            3(NXDOMAIN)<o:p></o:p></p>
          <p class="MsoNormal"><o:p> </o:p></p>
          <p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#00629F;mso-fareast-language:EN-AU">Mike
                Manning</span></b><span
style="font-size:13.5pt;font-family:"Arial",sans-serif;color:black;mso-fareast-language:EN-AU"><br>
            </span><b><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:gray;mso-fareast-language:EN-AU">Network
                Engineer</span></b><span
              style="font-size:13.5pt;color:black;mso-fareast-language:EN-AU"><br>
              <br>
            </span><b><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#00629F;mso-fareast-language:EN-AU">Matilda
                Internet</span></b><span
              style="font-size:13.5pt;color:black;mso-fareast-language:EN-AU"><br>
            </span><span
style="font-size:7.5pt;font-family:"Tahoma",sans-serif;color:gray;mso-fareast-language:EN-AU">________________</span><span
style="font-size:13.5pt;color:black;mso-fareast-language:EN-AU"><br>
              <br>
            </span><span
style="font-size:7.5pt;font-family:Wingdings;color:#A18C4C;mso-fareast-language:EN-AU">(</span><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#A18C4C;mso-fareast-language:EN-AU">Telephone
              +61 7 4953 0711</span><span
style="font-size:13.5pt;font-family:"Arial",sans-serif;color:#A18C4C;mso-fareast-language:EN-AU"><br>
            </span><span
style="font-size:7.5pt;font-family:Wingdings;color:#A18C4C;mso-fareast-language:EN-AU">(</span><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#A18C4C;mso-fareast-language:EN-AU">Fax
              +61 7 4849 5000<br>
              29 Gregory Street, Mackay, QLD 4740, Australia<br>
            </span><span
style="font-size:7.5pt;font-family:Wingdings;color:#00629F;mso-fareast-language:EN-AU">*</span><span
style="font-size:13.5pt;color:black;mso-fareast-language:EN-AU"> </span><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#00629F;mso-fareast-language:EN-AU">Email</span><span
style="font-size:13.5pt;color:black;mso-fareast-language:EN-AU"> </span><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#00629F;mso-fareast-language:EN-AU"><a
                href="mailto:mike@matilda.net.au" moz-do-not-send="true"><span
                  style="color:purple">mike@matilda.net.au<br>
                </span></a>Website</span><span
              style="font-size:13.5pt;color:black;mso-fareast-language:EN-AU"> <a
                href="http://www.matilda.net.au/" moz-do-not-send="true"><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:purple">www.matilda.net.au<br>
                </span></a><br>
              <br>
            </span><span
style="font-size:7.5pt;font-family:"Arial",sans-serif;color:gray;mso-fareast-language:EN-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.</span><span
style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:black;mso-fareast-language:EN-AU"><o:p></o:p></span></p>
          <p class="MsoNormal"><o:p> </o:p></p>
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        <pre class="moz-quote-pre" wrap="">_______________________________________________
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</pre>
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      <pre class="moz-quote-pre" wrap="">_______________________________________________
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