Why is Microsoft Outlook requesting proof of IP address ownership?

Email marketer from Gmass Blog explains that Microsoft, like other email providers, might request proof of IP ownership to ensure the sender is adhering to responsible sending practices and maintaining a clean email list. They want to prevent senders from buying lists and spamming.

Email marketer from Email Geeks shares that Microsoft requested part of the contract with their MTA showing the rented IP addresses and then a recent email from their MTA proving the IP is rented by them.

Email marketer from Email on Acid explains that Microsoft might request IP ownership proof in cases where the sender's reputation is poor or unknown. They want to verify the sender is a legitimate business and not a spammer.

Email marketer from Email Geeks shares that clarifying ownership of IP addresses without providing documentation was sufficient to move things along when receiving similar requests at an ESP.

Email marketer from SparkPost Blog explains that Microsoft might require proof of IP ownership if there are inconsistencies with SPF or DKIM records or when the sending IP lacks a proper PTR record linking back to the domain. This is done to confirm that the sender is authorized to use the IP.

Email marketer from Mailjet Blog shares that Microsoft may ask for IP ownership proof as part of their IP warm-up best practices. This ensures new senders establish a good sending reputation.

Email marketer from Email Geeks explains showing the whois records for that IP address has been enough when receiving such requests and agrees it's likely an incorrect pre-defined reply.

Email marketer from Reddit mentions that Microsoft, amongst other ESP's may ask for proof to verify you aren't a spammer if you have just acquired the IP.

Email marketer from EmailGeekForum notes that Microsoft may request IP proof if the IP is on a known blacklist and the sender is trying to get delisted. This helps ensure the IP is no longer being used for spam.

Email marketer from Stack Overflow responds that Microsoft is asking for proof to cut down on spoofing and phishing by ensuring that the IP address is legitimately owned by the sender and not being used maliciously.

Email marketer from Litmus explains that Microsoft may ask for proof of IP ownership to verify that the sender has permission to send from that IP and to prevent domain spoofing.

Expert from Email Geeks believes Microsoft might be trying to prevent spammers from repeatedly getting delisted under different company names by verifying IP ownership.

Expert from Spam Resource explains that Microsoft requests IP ownership verification to confirm that the IP has a legitimate sending history and to prevent spammers from using newly acquired or leased IPs without proper authorization. This helps them maintain the quality of their service.

Expert from Email Geeks suggests Microsoft may have implemented new processes for IP verification.

Expert from Word to the Wise responds that Microsoft often asks for proof of IP ownership, particularly during IP onboarding. This is to ensure that the sender has the right to send from that IP and follows best practices to reduce their spam complaints.

Expert from Email Geeks suggests the IP address verification request could be due to existing history on the IP, and Microsoft is verifying if the user is the cause or someone new.

Documentation from Google explains that Microsoft might request IP ownership verification in cases of high spam complaints associated with an IP. They need to ensure the current owner is not a malicious actor.

Documentation from IETF mentions that Microsoft may request IP ownership verification if the reverse DNS (PTR record) does not match the sending domain. This discrepancy can raise red flags.

Documentation from RFC explains that Microsoft might require proof of IP ownership if the sending IP is not properly included in the SPF record for the domain. This is a fundamental authentication check.

Documentation from Microsoft's SNDS (Smart Network Data Services) indicates that they may request proof of IP ownership when an IP address demonstrates suspicious activity or sudden changes in sending patterns, to ensure it hasn't been compromised.

Documentation from Microsoft Learn explains that Microsoft may request information about IP address ownership to verify the sender's reputation and legitimacy, especially for new or unestablished senders. This helps prevent spam and abuse.