What is my IPv6 hostname?

Your IPv6 hostname

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More about your connection

What is IPv6 reverse DNS?

The displayed name is the reverse DNS hostname of your IPv6 address: the name that the owner of the address, usually your ISP, has published for it. If no record exists, the tool shows “Not detected” or your address itself.

How IPv6 reverse DNS works

IPv6 reverse lookups work like IPv4 reverse DNS, using PTR records, but in a different zone: ip6.arpa. The address is written out in full, split into single hexadecimal digits (nibbles) and reversed. For 2001:db8::1 the lookup name becomes:

1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa

Why IPv6 hostnames are less common

Your ISP typically gives your home network a whole /56 or /64 block, with billions of possible addresses, and your devices pick addresses inside it themselves. Most ISPs don’t generate a record for each address. Some return a generic name for the whole block, and many return nothing at all.

When an IPv6 hostname matters

  • Mail servers sending over IPv6 need a PTR record that matches their forward DNS name, or major providers will reject their email.
  • Servers and network equipment are easier to identify in logs and traceroutes with meaningful names.
  • Hosting providers usually let you set a custom PTR record for your server’s IPv6 address in their control panel.

Looking up an IPv6 hostname yourself

  • Windows, macOS or Linux: nslookup 2001:db8::1
  • macOS or Linux: dig -x 2001:db8::1

Frequently asked questions

Why doesn't my IPv6 address have a hostname?

Many ISPs don’t create reverse DNS records for customer IPv6 addresses. A single customer can have trillions of addresses, and devices change them often, so writing a record for each one isn’t practical. This doesn’t affect browsing.

Is my IPv6 hostname the same as my IPv4 hostname?

Not necessarily. The two protocols use separate reverse DNS zones, so an ISP can set different names, or a name for only one of them.

Do I need an IPv6 hostname to send email?

Only if you run your own mail server over IPv6. Major email providers require a valid reverse DNS record that matches the sending address, on IPv6 just as on IPv4.