https://www.suped.com/learn/email-deliverability/how-can-i-determine-the-isp-or-mailbox-provider-of-an-email-address
How can I determine the ISP or mailbox provider of an email address? - Suped
Learn how to determine the ISP or mailbox provider of an email address using DNS lookups (MX, PTR records) and email headers. Essential for email...
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