Enter an IP address to see the hostname its PTR record returns, and whether that hostname resolves straight back to the same IP.
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Lower stack cost. Back in the inbox. Built to send at any scale.
We rebuild it properly: secondary domains, inboxes, SPF, DKIM and DMARC set to enforcement, warmup and safe sending limits, blacklist monitoring on top. Send-ready in about 17 days. No campaigns, no copy, no lead lists. Infrastructure only.
Almost a decade building cold outreach infrastructure, including his own sending and verification stack built from scratch. 20+ B2B clients at companies worth $10M and above, all in tier one countries.
Free · Written plan + fixed price · No sales call required
Every IP address can publish a PTR record, which is a reverse DNS entry that names the host behind the address. This tool builds the reversed lookup name for the IP you enter, asks public DNS for its PTR records, and shows the hostname or hostnames that come back. It then does the second half of the check that receiving servers do: it resolves the first hostname forward again and compares the address it gets with the one you started from. When both directions agree, the address has forward confirmed reverse DNS.
A good sending server has one clear PTR hostname, and that hostname points back to the same IP. No PTR at all is common on cloud and office addresses, and receivers treat it as a bad sign on a mail server. A PTR that returns a generic provider name is better than nothing but still weak. The fail that matters is a mismatch: the PTR names one host, and that host resolves somewhere else. That is the setup that trips spam filters even when SPF and DKIM are right, so compare it with the IP Blacklist Checker when an address is already in trouble.
PTR records are set by whoever owns the IP address, not by whoever owns your domain, so the fix usually starts with a support ticket or a control panel at your hosting or inbox provider. Ask them to set the PTR to the exact hostname your mail server announces, then make sure that hostname has an A record pointing back to the same IP. Allow time for DNS to settle and run this check again. If the IP is shared or the provider will not set PTR, that address was never meant to send mail: move sending to an address your provider will name properly, and confirm its mail records in the MX Record Checker.
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