Domaincheck

Domaincheck

Domain Availibility Check (DCHK)

Since 23 September 2008, DENIC makes available a new information service, the so-called DCHK (DomainCHecK) that serves for querying the status of .de  domains. To enable easy and uncomplicated utilization of the service, DENIC places at disposal a compiled DCHK client and its source code (in Java) under an LGPL license (version 3.0) as open source software for downloading. Please do not hesitate to address questions, comments and feedback by e-mail to iris-feedback[at]denic[dot]de. We look forward to it.

The new service is based on the Internet standard RFC5144 published in February 2008. DENIC was involved considerably in the development of this standard, which describes the so-called "Domain Availability Check" function (DCHK). Compared to the whois query the system offers the following advantages:

• DCHK is based on Unicode and thus supports umlauts and special characters in all languages.
• DCHK uses the XML standard to define universal query and response formats.
• DCHK transmits queries via the stateless UDP protocol.
• DCHK compresses query and response.
• DCHK can find out the status of several domains by one single query.
• DCHK remains efficient in operation even with large query volumes.
• DCHK recognizes the authoritative server automatically by using the Dynamic Delegation Discovery System.

The table below gives a survey of the messages sent by DCHK and their equivalents in whois.

DCHK-Meldung	meaning	whois-equivalent
active	Domain is registered and connected.	connect
inactive	Domain is registered but not connected.	failed
nameNotFound	The domain is available for registration.	free
invalidName	The syntax of the domain name is invalid, e.g. $&%$%.de. OR The syntax of the domain is valid but the name is not allowed to be registered.	.de: invalid

You find further information and the software for downloading on a background page.