PTR
Pointer (Reverse DNS)
PTR records map an IP address back to a hostname. Learn how reverse DNS works, why it matters for email deliverability, and how to request one.
Record Type
PTR
Category
Email Delivery
Email Delivery
RFC
RFC 1035
RFC 1035
Email Relevant
Yes
Yes
Format
PTR <hostname>.
Example
PTR mail.example.com.
TTL Guidance
3600–86400 s; managed by your ISP or hosting provider — not in your own zone
3600–86400 s; managed by your ISP or hosting provider — not in your own zone
💬 What This Record Does
A PTR record is the reverse of an A record — it maps an IP address to a hostname. Reverse DNS (rDNS) is stored in the special ".in-addr.arpa" zone for IPv4 or ".ip6.arpa" for IPv6. PTR records are managed by whoever owns the IP block (your ISP or hosting provider), not by you in your own domain zone. For email, many receiving servers require that your sending IP has a PTR record that matches its forward A record — this is called FCrDNS (Forward-Confirmed reverse DNS).
Common Uses
- Proving that a mail server IP belongs to a legitimate operator (FCrDNS check)
- Identifying which hostname is associated with an IP in server logs
- Improving email deliverability — many spam filters penalise missing PTR records
⚠️ Watch Out For
- You cannot set PTR records in your own DNS zone — they must be configured by the IP block owner.
- A mismatch (PTR hostname doesn't resolve back to the original IP) breaks FCrDNS and can cause mail rejection.
- Shared hosting IPs often have generic PTR records — this can hurt deliverability. Use a dedicated IP where possible.