Reverse DNS
Find the hostname assigned to any IPv4 or IPv6 address via PTR records. Free, instant reverse DNS lookup — useful for mail server checks and abuse reports.
About this Reverse DNS tool
Reverse DNS (rDNS) maps an IP address back to its hostname using PTR records, the reverse of an A or AAAA lookup. Mail servers and abuse-tracking systems rely on it to verify sender legitimacy.
How to use the Reverse DNS
- Step 1. Paste an IPv4 or IPv6 address.
- Step 2. CheckHub queries the in-addr.arpa or ip6.arpa zone for a PTR record.
- Step 3. Read the matched hostname and TTL.
Frequently asked questions
- Why does my IP not have reverse DNS?
- PTR records are managed by the IP block owner (often your ISP). Many residential IPs return generic hostnames or no record at all.
- Why does my mail server fail without rDNS?
- Major mail providers (Gmail, Outlook) reject mail from IPs without forward-confirmed reverse DNS to limit spam from misconfigured hosts.
Related DNS Tools
- DNS Propagation Checker - Check DNS propagation across global servers
- DNS Lookup - Look up DNS records for any domain
- DNS Compare - Compare DNS records between two domains
- DNSSEC Checker - Verify DNSSEC configuration
- NS Lookup - Look up nameservers
- MX Lookup - Look up mail server records