Using our WHOIS Server
We provide a WHOIS server at whois.iana.org for looking up information for a number of registries maintained as part of the IANA functions:
- Root Zone Registry — the WHOIS database of delegations from the DNS root zone (also know as top-level domains).
- .INT Registry — the database of .INT domain registrations, used by intergovernmental treaty organisations.
- .ARPA Registry — the database of .ARPA domain registrations
- IPv4 and IPv6 allocations — the registry of allocations made from the global IPv4 and IPv6 address spaces, plus specially designated allocations described in technical standards.
- Autonomous System (AS) number allocations — the registry of allocations made from the global AS number space.
Queries supported
Here are some illustrative examples of queries supported by the WHOIS Server:
| Query type | Examples |
|---|---|
| Domain names | icann.org, .org, who.int |
| IP addresses | 192.168.1.1, 10.0.4.5 |
| IP address ranges | 192.168.0.0-192.168.0.255, 192.0.0.0/24, 192/24 |
| AS numbers | 542, AS542 |
Response format
Data is returned in a colon delimited "key: value" format. Comment lines begin with a "%" symbol. Text is encoded using UTF-8.
Referrals
If our WHOIS server determines there is a more specific answer to the query you have received, it will return the most specific answer it has available. If we know of a WHOIS server that should be more authoritative for the specific record, we also return a "refer:" line. You may wish to send a WHOIS query to that server to find more information about the resource.
This behaviour occurs, for example, if you query for a domain like "icann.org". The root zone database only has authoritative data for ".org", but we will provide a referral to the .org WHOIS server which has more information about the second-level registration. Such behaviour will also happen for IP address allocations that are more specific than the records in IANA's databases.