Domain/IP/ASN registration data query

Use Case

  • Get registration data for all Domain/IP/ASN at one place.

  • Determin if the domain name you want has been registered.

Usage Guide

  1. Input domain name, IP address or ASN to query

    In the input box of ‘Domain/IP/ASN’, your public IP address is filled automatically for convenience.

    Click on the input box, the public IP address will disappear so as to enter other values.

    After the public IP address disappears, only you can edit the values in the input box.

  1. Domain name format

  2. IP address format

    • IP version 4 address (IPv4), e.g.

    • IP version 6 address (IPv6), e.g. 2001:dc7:1000:0:0:0:0:1

    • IP version 4 address block (IPv4 CIDR), e.g.

    • IP version 6 address block (IPv6 CIDR), e.g. 2001:0dc7::/32

  3. AS number format

    • Only AS number, e.g. 1902

    • Has prefix ‘AS’(case insensitive), e.g. AS1902

    • Has prefix ‘ASN’(case insensitive), e.g. AS1902

  4. ‘Domain/IP/ASN’ Input Box Input Format

    • The above domain name, IP address, AS number format

    • Any string. Automatically recognize the domain name, IP address, or AS number at the beginning of the string.

  1. Select the protocol

    1. WHOIS protocol

      It’s early protocol, and each domain name service provider will deploy the WHOIS server, and the results are readable for human.

    2. RDAP protocol

      This protocol want to replace WHOIS, and now the two protocols coexist, and the result of it is for computers, so the sechndary processing is required.

  2. Select data source

    1. Local server cache

      If someone queries a domain name, IP address, or AS number, the result is cached in this server to improve the access speed. The cache time is no more than 5 days.

      If the result is not cached or the cache time is more than 5 days, then the program will query the remote WHOIS/RDAP server.

    2. Remote WHOIS/RDAP server

      If choosing this option, no matter whether there is a cache, the program will directly query the remote WHOIS/RDAP server.

  3. Click button of query

    After clicking, It will run the query program in this server. If there is the result in the cache, the access will be very fast. If querying the remote server, the access may be slow, depending on the remote server.

    It is possible that the remote server does not respond within the specified time, which is a timeout; it is also possible that the remote server will limit access speed or deny the service because of querying too much.

  4. Examine Results

    The result of the query is a list, there may be multiple results, the first result is generally the data from the database of domain-registered service provider, and this data is relatively accurate.

    The following results are generally the data from the database of the high-level service provider or ICANN, This data is reported by the domain-registered service provider, and usually not so in time and accurate.

    If it is a cache data, then the latest cache time is given, which is the China Standard Time(CST, +0800).

    If cannot find registration data, It will provide links to help you.

    If there is an error about format or there are other problems, It will give some tips.

Background Knowledge

  • Domain name

    Domain names are a key part of the Internet infrastructure. They provide a human-readable address for any web server available on the Internet.

    Any Internet-connected computer can be reached through a public IP address, either an IPv4 address (e.g. or an IPv6 address (e.g., 2027:0da8:8b73:0000:0000:8a2e:0370:1337).

    Computers can handle such addresses easily, but people have a hard time finding out who’s running the server or what service the website offers. IP addresses are hard to remember and might change over time.

    To solve all those problems we use human-readable addresses called domain names.

    Refer to Domain name

  • IP Address

    An Internet Protocol address (IP address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. An IP address serves two main functions: host or network interface identification and location addressing.

  • ASN

    An autonomous system (AS) is a collection of connected Internet Protocol (IP) routing prefixes under the control of one or more network operators on behalf of a single administrative entity or domain that presents a common, clearly defined routing policy to the Internet.

    A unique ASN is allocated to each AS for use in BGP routing. ASNs are important because the ASN uniquely identifies each network on the Internet.

  • Whois协议

    WHOIS Protocol Specification

  • RDAP协议

    RDAP is specified as a suite Internet Request for Comments (RFC) documents.

    • rfc 7480 – http usage in the registration data access protocol (rdap)

    • rfc 7481 – security services for the registration data access protocol (rdap)

    • rfc 7482 – registration data access protocol (rdap) query format

    • rfc 7483 – json responses for the registration data access protocol (rdap)

    • rfc 7484 – finding the authoritative registration data (rdap) service

    • rfc 7485 – inventory and analysis of whois registration objects

    • rfc 8521 – registration data access protocol (rdap) object tagging