Domaincheck

Domaincheck - Background

How does DCHK work?

DCHK is a service that is based on the Internet Registry Information Service (IRIS) Standard (RFC3981). IRIS, together with all registry schemes derived from it like DREG (for domain registration) or AREG (for address registration, e.g. of IP addresses), shall become the designated successor of the currently used whois protocol.

DCHK is designed to be used with LWZ (a lightweight transfer protocol using compression, compare RFC4993), which is based on UDP (User Datagram Protocol) instead of TCP (Transmission Control Protocol). When using UPD it is not necessary to establish a connection to the server. The client simply sends a data packet to the server and receives a response. With DCHK and LWZ transfer, the domain status query thus becomes extremely effective and, given the special DCHK data structure, well provides for efficient operation. Moreover, one cannot only query the availability of the domain but also some supplementary information like the time stamp of the database update.

The structured query of the data applies the XML standard of the World Wide Web Consortium. One of the functions of that standard is to exchange information between different computer systems. The data can then be further processed and, depending on the respective configuration, be displayed in form of a table in one system and in form of a graph in another. The code examples following below demonstrate how the information on the status of a .de domain is transmitted by the Domain Availability Check.
Example of usage: query of status of the domain "denic.de".

Query:

<request xmlns="urn:ietf:params:xml:ns:iris1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:ietf:params:xml:ns:iris1 iris.xsd">
 <searchSet>
  <lookupEntity registryType="urn:ietf:params:xml:ns:dchk1" entityClass="domain-name" entityName="denic.de" />
 </searchSet>
</request>

Response:

<?xml version="1.0" encoding="UTF-16"?>
 <iris1:response xmlns:iris1="urn:ietf:params:xml:ns:iris1">
  <iris1:resultSet>
   <iris1:answer>
    <urn:domain authority="de" entityClass="domain-name" entityName="denic.de" registryType="dchk1"
xmlns:urn="urn:ietf:params:xml:ns:dchk1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="urn:domainType">
      <urn:domainName>example-domain.de</urn:domainName>
       <urn:status>
        <urn:active/>
       </urn:status>
          </urn:domain>
   </iris1:answer>
  </iris1:resultSet>
 </iris1:response>
Example of usage: query of the ENUM domain of DENIC