While none of our MTAs are blocked (yet), once we successfully log in to SNDS (https://sendersupport.olc.protection.outlook.com/signin-oidc) we are greeted with a blank page.
Another Zimbra Partner reports that their IPs are being blocked, so their mail queues are up to thousands of emails. They are using that list of Microsoft 365-hosted domains as a marketing tool. If our IPs become blocked we will do the same. Any chance though that Microsoft is fending off some sort of attack, and we are all just collateral damage? Would be nice if Microsoft posted something publicly... (perhaps I have missed it?) Regards, Mark -- _________________________________________________________________ L. Mark Stone, Founder North America's Leading Zimbra VAR/BSP/Training Partner For Companies With Mission-Critical Email Needs Winner of the Zimbra Americas VAR Partner of the Year - Two Years Running ! ----- Original Message ----- | From: "Gellner, Oliver via mailop" <[email protected]> | To: [email protected] | Sent: Tuesday, February 24, 2026 2:34:20 PM | Subject: Re: [mailop] Outlook rate limiting, just us? |> On 24.02.2026 at 18:12 schrieb Paul Smith* via mailop wrote: |> |> On 24/02/2026 16:13, Paul Smith* via mailop wrote: |>>> On 24/02/2026 12:45, Gellner, Oliver via mailop wrote: |>>> |>>> We receive the same error messages for all servers since 2026-02-23 18:45 UTC. |>>> It's unlikely that Microsoft suddenly received spam from all IP addresses of |>>> all kind of unrelated organizations yesterday evening. Probably some algorithm |>>> went nuts there. |>> |>> I thought we were being *rate limited*, but we're not, nothing at all is going |>> out to outlook.com, hotmail.com, etc. Mail to business M365 is going out fine. |> |> As it's the same /29 range as our other servers, that would suggest it's not a |> 'bad neighbour' problem. | | It‘s not a neighborhood issue. We have a whole /24 in which only two IP | addresses are able to make connections on port 25, and those two are | rate-limited as well. | | — | BR Oliver | ________________________________ | | dmTECH GmbH | Am dm-Platz 1, 76227 Karlsruhe * Postfach 10 02 34, 76232 Karlsruhe | Telefon 0721 5592-2500 Telefax 0721 5592-2777 | [email protected]<mailto:[email protected]> * www.dmTECH.de<http://www.dmtech.de> | GmbH: Sitz Karlsruhe, Registergericht Mannheim, HRB 104927 | Geschäftsführer: Christoph Werner, Martin Dallmeier, Roman Melcher | ________________________________ | Datenschutzrechtliche Informationen | Wenn Sie mit uns in Kontakt treten, beispielsweise wenn Sie an unser | ServiceCenter Fragen haben, bei uns einkaufen oder unser dialogicum in | Karlsruhe besuchen, mit uns in einer geschäftlichen Verbindung stehen oder sich | bei uns bewerben, verarbeiten wir personenbezogene Daten. Informationen unter | anderem zu den konkreten Datenverarbeitungen, Löschfristen, Ihren Rechten sowie | die Kontaktdaten unserer Datenschutzbeauftragten finden Sie | hier<https://www.dm.de/datenschutzerklaerung-kommunikation-mit-externen-493832>. | _______________________________________________ | mailop mailing list | [email protected] | https://list.mailop.org/listinfo/mailop _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
