You're not alone - we found a similar issue when testing services on the recently launched Azure instances in New Zealand.
The ranges that Microsoft acquired for use in the new region were previously used by dialup/adsl/fibre end users. This resulted in the same rejections by Google and M365. We managed to work with MS on this listing with Spamhaus (where they were getting blocked), but we never pursued the issue with Google as we didn't continue our deployment in that region. Graeme -----Original Message----- From: mailop <mailop-boun...@mailop.org> On Behalf Of Joe Muller via mailop Sent: Friday, May 2, 2025 11:19 AM To: mailop@mailop.org Subject: [mailop] Google Rejecting Mail from Static IP with 550-5.7.1 We have a colocated customer who is reporting their outbound mail is being rejected when emailing gmail.com addresses. The customer's mail server is at 157.131.30.2, part of a larger block we are using for business static IP customers. The message their receive from Google (on 20250426) is as follows: <redac...@gmail.com>: host gmail-smtp-in.l.google.com[142.251.2.26] said: 550-5.7.1 [157.131.30.2] The IP you're using to send mail is not authorized to 550-5.7.1 send email directly to our servers. Please use the SMTP relay at your 550-5.7.1 service provider instead. For more information, go to 550 5.7.1 https://support.google.com/mail/?p=NotAuthorizedError 41be03b00d2f7-b15f88876f4si8236173a12.185 - gsmtp (in reply to end of DATA command) Does Google operate its own list similar to the SpamHaus PBL that would cause mail to be rejected? A lookup in SpamHaus' tool shows no problems. Anyone here from Google or with similar experience willing to contact me on or off-list with more information? Thanks. -- Joe Muller System Operations Sonic. _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop Email secured by Trustwave advanced threat protection. Learn more at https://trus.tw/mailmarshal This transmission may contain information that is privileged, confidential, and/or exempt from disclosure under applicable law. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or use of the information contained herein (including any reliance thereon) is STRICTLY PROHIBITED. If you received this transmission in error, please immediately contact the sender and destroy the material in its entirety, whether in electronic or hard copy format. _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
