Setting up reverse DNS for your email server involves configuring PTR (Pointer) records in your DNS settings. Here are the steps:
Log in to your DNS hosting provider. Navigate to the DNS management area. Create a new PTR record for your email server's IP address. Map the IP address to your domain name. Save the changes and wait for the DNS to propagate.
It's important to note that you may need to contact your ISP or hosting provider to set up reverse DNS, as they often control the PTR records.