PUBLIC DNS
Look up a reverse DNS PTR record.
Convert an IPv4 address to in-addr.arpa and return the published PTR name.
PTR maps an IP address back to a hostname. Receiving servers sometimes inspect it on SMTP connections.
MailerZ customer domains do not require you to publish PTR. Missing PTR is not a MailerZ setup failure. For a scored MailerZ readiness scan across MX, leftover routes, SPF, DKIM, and DMARC, use Troubleshooting.
Open the full DNS diagnostic · Simulate a route in the Email Routing Lab
Cited standard: RFC 1035
PTR maps an IP address back to a hostname. Receiving servers sometimes inspect it on SMTP connections.