Of course, while it is good that it is listed 'somewhere'..
For this type of critical infrastructure, eg.
Allow
Optional
Notes: POP3, IMAP4, SMTP Client traffic Yes outlook.office365.com,
smtp.office365.com
13.107.6.152/31, 13.107.18.10/31, 13.107.128.0/22, 23.103.160.0/20,
40.96.0.0/13, 40.104.0.0/15, 52.96.0.0/14, 131.253.33.215/32,
132.245.0.0/16, 150.171.32.0/22, 204.79.197.215/32, 2603:1006::/40,
2603:1016::/36, 2603:1026::/36, 2603:1036::/36, 2603:1046::/36,
2603:1056::/36, 2620:1ec:4::152/128, 2620:1ec:4::153/128,
2620:1ec:c::10/128, 2620:1ec:c::11/128, 2620:1ec:d::10/128,
2620:1ec:d::11/128, 2620:1ec:8f0::/46, 2620:1ec:900::/46,
2620:1ec:a92::152/128, 2620:1ec:a92::153/128
TCP: 587, 993, 995, 143
Why is there no PTR assignments? Without that, your systems of course
might suffer a delay in connections, or worse. Transparency is key to
email, and a standard naming convention for those would help.
Not to mention, RFC compliance.
host 13.107.6.152
Host 152.6.107.13.in-addr.arpa. not found: 3(NXDOMAIN)
On 2025-12-16 16:37, William Rall wrote:
If you're talking about machines making IMAP or SMTP connections to your
servers as a part of Outlook access, you should expect to see
connections originating from the set of IP addresses listed here:
Microsoft 365 URLs and IP address ranges - Microsoft 365 Enterprise |
Microsoft Learn <https://learn.microsoft.com/en-us/microsoft-365/
enterprise/urls-and-ip-address-ranges?view=o365-worldwide#exchange-online>
Thanks,
William Rall
*From:*mailop <[email protected]> *On Behalf Of *Michael Wise
via mailop
*Sent:* Tuesday, December 16, 2025 12:53 PM
*To:* Michael Peddemors <[email protected]>; [email protected]
*Subject:* Re: [mailop] [EXTERNAL] Microsoft, can you shed light on
this?? Outlook Live clients and account discovery..
Are they listed in the relevant SPF record?
Aloha,
Michael.
--
*Michael J Wise*
MicrosoftCorporation| Spam Analysis
"Your Spam Specimen Has Been Processed."
Open a ticket for Hotmail <http://go.microsoft.com/fwlink/?LinkID=614866> ?
-----Original Message-----
From: mailop <[email protected] <mailto:mailop-
[email protected]>> On Behalf Of Michael Peddemors via mailop
Sent: Tuesday, December 16, 2025 11:53 AM
To: [email protected] <mailto:[email protected]>
Subject: [EXTERNAL] [mailop] Microsoft, can you shed light on this??
Outlook Live clients and account discovery..
Microsoft is making it REALLY hard to determine legitimate attempts at
authentication, or authentication discovery, as the IPs they use have NO
differentiators from bad IPs on their networks.
The following appear to be:
(even though they are being part of the new Outlook email client
routing system):
40.99.85.29 (MY)
52.98.116.53 (SG)
40.99.104.101 (KR)
40.99.53.37 (JP)
52.98.49.141 (MY)
40.99.32.173 (JP)
they are reported to be coming from various remote countries based on
the various GeoIP DB and are being blocked by the country auth.
There is no consistency, and even from official MS Outlook IPs, we no
longer even have PTR's on them.
Another company wanting to make it difficult to run your own email
servers..
Can we get a little more transparency on which IPs are actually part of
the MS routing for Outlook authentication/discovery IPs?
--
"Catch the Magic of Linux..."
------------------------------------------------------------------------
Michael Peddemors, President/CEO LinuxMagic Inc.
Visit us at https://nam06.safelinks.protection.outlook.com/?
url=http%3A%2F%2Fwww.linuxmagic.com%2F&data=05%7C02%7Cmichael.wise%40microsoft.com%7Cabfe0bb64bad48242a3908de3cdd1389%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C639015117391446267%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=haWq1CA%2F0%2BhMpbCJg7%2BuAojLUGG%2Biuq8wUv54U6eRfI%3D&reserved=0 <http://www.linuxmagic.com/> @linuxmagic
A Wizard IT Company - For More Info https://
nam06.safelinks.protection.outlook.com/?
url=http%3A%2F%2Fwww.wizard.ca%2F&data=05%7C02%7Cmichael.wise%40microsoft.com%7Cabfe0bb64bad48242a3908de3cdd1389%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C639015117391478287%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=08MyUMfylbZpIuxBMmjcOeJ4xOxIM6RMcQnb085wGbQ%3D&reserved=0 <http://www.wizard.ca/>
"LinuxMagic" a Reg. TradeMark of Wizard Tower TechnoServices Ltd.
------------------------------------------------------------------------
604-682-0300 Beautiful British Columbia, Canada
_______________________________________________
mailop mailing list
[email protected] <mailto:[email protected]>
https://nam06.safelinks.protection.outlook.com/?
url=https%3A%2F%2Flist.mailop.org%2Flistinfo%2Fmailop&data=05%7C02%7Cmichael.wise%40microsoft.com%7Cabfe0bb64bad48242a3908de3cdd1389%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C639015117391499316%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=5O3LPC2n8DYq%2FIAs957aZ7Oy7CrIYtv4yXhaWEJwAEU%3D&reserved=0 <https://list.mailop.org/listinfo/mailop>
_______________________________________________
mailop mailing list
[email protected]
https://list.mailop.org/listinfo/mailop
