Netspace India

    Reverse DNS Lookup (PTR)

    Find the hostname associated with any IPv4 or IPv6 address.

    What is a PTR record?

    A reverse DNS lookup (also called PTR lookup) does the opposite of normal DNS — given an IP address, it returns the hostname assigned to it. PTR records live in the in-addr.arpa zone (IPv4) or ip6.arpa zone (IPv6) and are typically controlled by whoever owns the IP block (your hosting provider).

    Reverse DNS is especially important for email servers: most receiving mail servers reject messages from a sending IP that doesn't have proper rDNS set up. If you're running an email server or shared hosting isn't cutting it, a Netspace India dedicated server with a dedicated IP lets you configure PTR cleanly for mail delivery.

    Common uses

    • Verify your mail server's reverse DNS is set (critical for email delivery)
    • Identify who owns an IP address appearing in your server logs
    • Debug email bounces from strict receivers (Gmail, Outlook)
    • Audit IP space you've been assigned by your hosting provider

    Frequently Asked Questions

    What is reverse DNS?
    Reverse DNS (rDNS) lookup takes an IP address and returns the hostname associated with it, using PTR records in the in-addr.arpa or ip6.arpa zones. It's the opposite of a normal (forward) DNS lookup.
    Who controls PTR records?
    The owner of the IP block — usually your hosting provider. For your own dedicated IP with full rDNS control, consider a Netspace India dedicated server.
    Why does rDNS matter for email?
    Most receiving mail servers (Gmail, Outlook, iCloud) check whether the sending IP has a matching PTR record. If not, your email is often rejected or flagged as spam. Use our MX lookup and TXT lookup to also verify your other email records.
    Can one IP have multiple PTR records?
    Technically yes, but strongly discouraged. Mail servers and other services typically expect exactly one PTR per IP.
    What's forward-confirmed reverse DNS (FCrDNS)?
    When an IP's PTR returns a hostname AND that hostname's A/AAAA record returns the original IP. Many mail receivers require this bidirectional match for email to be accepted.
    Why does my rDNS lookup return 'ENOTFOUND'?
    No PTR record is configured for that IP. Common for home/mobile IPs. If it's your server IP and you need rDNS, you may need a dedicated server plan rather than shared hosting.
    Related Netspace Service

    Dedicated Server with Dedicated IP + rDNS

    Netspace India dedicated servers come with a dedicated IPv4, free rDNS configuration, and India-located data centres.

    View Dedicated Servers →

    Other DNS Lookup Tools

    A Record Lookup

    IPv4 address for a domain

    AAAA Record Lookup

    IPv6 address for a domain

    MX Record Lookup

    Mail servers that accept email

    TXT Record Lookup

    SPF, DKIM, DMARC, verification

    CNAME Lookup

    Canonical name aliases

    NS Lookup

    Nameservers for a domain

    SOA Record Lookup

    Start of authority info

    DNS Propagation Check

    Check 6 global resolvers at once

    Need a domain, hosting or DNS management?

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