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Reverse DNS Lookup
A PTR record maps an IP address back to a hostname. Mail servers check it before accepting mail, and it is the name a traceroute shows for each hop. Enter an IPv4 or IPv6 address and the lookup builds the in-addr.arpa or ip6.arpa name for you.
About PTR records
What the answer tells you
- Reverse DNS is controlled by whoever owns the IP address — your hosting provider or ISP — not by the DNS host of your domain.
- For a mail server, the PTR should name a host whose A record points back at the same address. Many receivers reject mail when it does not.
- An address without a PTR record is common for home connections and for servers that were never given one.
34.216.184.93.in-addr.arpa. 3600 IN PTR example.com.
Record types
Look up any record type
Each type has a page of its own, explaining what the record does and what to look for in the answer.
- AA Record LookupIPv4 address
- AAAAAAAA Record LookupIPv6 address
- CNAMECNAME LookupAlias
- MXMX LookupMail servers
- TXTTXT Record LookupText, SPF and DMARC
- NSNS LookupNameservers
- SOASOA Record LookupZone authority
- CAACAA Record LookupCertificate authorities
- SRVSRV Record LookupService locations
- PTRReverse DNS LookupReverse DNS (PTR)
Questions
Frequently asked questions
- How do I change the PTR record for my server?
- Ask the provider that assigned the IP address. Most hosting providers let you set it in their control panel, often only once the hostname's A record already points at the address.
- Why is my mail rejected over reverse DNS?
- The sending server's IP address has no PTR record, or it names a host that does not resolve back to the same address. Set a PTR that matches the hostname your mail server announces.
- What is DNS propagation?
- DNS does not push changes out. Each resolver keeps an answer for its TTL and only asks again once that runs out, so after a change different resolvers return old and new answers for a while. When every column here agrees with the authoritative one, the change has reached them.
- What does the authoritative column show?
- The answer from one of the domain's own nameservers, which never comes from a cache. It shows what the zone says right now; the resolver columns show what the internet has cached.