royal guard standing near lamp post
Photo by Samuel Wölfl on Pexels.com

I have recently received a question that what RBL is used by Microsoft. I searched through many Microsoft articles but but none of them says about any RBL, but suddenly I came across a smtp response, which clarified that Microsoft is certainly using services of spamhaus. Hence their sender.office.com is using spamhaus in backend.

Here is the smtp conversation when i did telnet to alwayslearn-xyz.mail.protection.outlook.com on TCP 25 and received this errror.

220 MA1IND01FT004.mail.protection.outlook.com Microsoft ESMTP MAIL Service ready at Thu, 25 Jul 2019 18:58:15 +0000
ehlo sj.mail.com
250-MA1IND01FT004.mail.protection.outlook.com Hello [103.79.171.59]
250-SIZE 157286400
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-STARTTLS
250-8BITMIME
250 SMTPUTF8
mail from: sj@sj.com
250 2.1.0 Sender OK
rcpt to:sourabh@alwayslearn.xyz
550 5.7.1 Service unavailable, Client host [103.79.171.59] blocked using Spamhaus. To request removal from this list see https://www.spamhaus.org/query/ip/%5B103.79.171.59%5D (AS16012612) [MA1IND01FT004.eop-IND01.prod.protection.outlook.com]

Domain spamhaus.jpg

Thank you for reading !

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