There are several ways to identify the ISPs involved in your email marketing campaigns:
Email Headers: Examining the email headers can provide insights into the ISPs involved in the email delivery process. Analytics and Reports: Use email marketing platforms that offer detailed analytics and reports to identify which ISPs your emails are being delivered to. Feedback Loops: Participating in ISP feedback loops allows you to receive notifications about spam complaints, helping you identify the ISPs. Third-Party Tools: Utilize third-party tools and services that specialize in email deliverability and ISP identification.