whois-Service

Certain domain data can be accessed via DENIC’s public information query service. This includes, for example, the information who is responsible for looking after a domain from the technical point of view, if ever there are any technical difficulties caused by the relevant domain or its use, which might lead to problems for others. In addition, the domain holder is indicated, so in case the domain is the source of an infringement of somebody else's rights, it will be possible to establish against whom to proceed, if need be. DENIC publishes this information in accordance with German data protection regulations. The name that has established for this service for querying the mentioned public data is "whois".

DENIC makes available two optional versions of the whois service: the domain query via a web-based front end (web-whois) and/or via a command-line interface (public-whois). Data about the domain holder (Holder) and the administrative contact (Admin-C) will be output exclusively by the web-whois.

For domain queries via the web-whois, DENIC provides a specific input mask on its web page where users can enter the sought domain name(s). To inhibit automated queries, the users must successfully decipher and confirm a security code (a so-called Captcha) before any information is output.

In case of the public-whois, the domain query is made via the command line of a dedicated whois client which is capable to query the DENIC whois server. Such client which supports all the parameters implemented by DENIC is made available for free download on the website of RIPE (Réseaux IP Européens). RIPE is the Regional Internet Registry which is responsible for the allocation of IP addresses in the European address space.

Besides its IDN-based whois server for .de domains (whois.denic.de) DENIC offers a separate whois server for querying ENUM domains under .9.4.e164.arpa (whois.enum.denic.de).

The examples following below also include data that will only be published in responses to whois queries if the domain holder has explicitly requested that data to be disclosed. The corresponding provisions are laid down in § 8 sentence 2 of the DENIC Domain Terms and Conditions and/or in § 8 sentence 2 of the DENIC ENUM Domain Terms and Conditions.

General Query-Related Hints

• Response to query of a domain gives only domain status (connect, failed, free, invalid)
• Domain data can only be queried via the flag "-T dn (domain)" or "-T ace,dn (domain)".
• Standard data output is in UTF-8. Other character sets can be specified via the flag "-C (Charset)".
• “HELP” query delivers an overview of all used parameters.
• “alive@whois” query checks if whois is up.

Queries regarding .de Domains

• Queries can be made either for the IDN domain (e.g.: đäňîċ-ţåŝŧďómãĵņ.de / denic.de) or, using an additional flag, for the ACE form (e.g.: xn--dnic-loa.de / denic.de).
• For IDN domains, the output always includes the IDN domain ("Domain:") as well as the ACE form ("Domain-ace:").
• The date of the last update of the queried data set ("Changed:") is output in ISO-8601 format:
  yyyy-mm-ddThh:mm:ss+(time zone) (for example: 2005-11-18T07:53:29+01:00)

Description of potential query flags:

Flag	Description
-C (Charset)	Specification of the selected In-/Output character set. Default: UTF-8. Admitted charsets are: US-ASCII, ISO-8859-1, UTF-8, UTF-16. The specification of the character set is case insensitive.
-T st|status domain|ace	Default; Specific query of domain status
-T st,ace	Specific query of ACE-string and domain status
-T dn|domain domain	Specific query of a domain data set
-T ace,dn ace	ACE form of domain. Specific query of ACE string and domain data set
-r domain	Turns off recursive lookups

Queries regarding ENUM Domains

• To query a phone number you must use the flag "-T dn:no (telephone number)" or "-T st:no (telephone number)".

Description of potential query flags:

Flag	Description
-T st:no|status:number telephone number	Default; Specified query of phone number according to domain status
-T dn:no telephone number	Specific query of the phone number of a domain data set

Notes on the Syntax of the Various whois Clients

There are different whois clients that do not all support the flags used by our whois server. Try two additional dashes before the actual flag or put the flag in quotation marks or use a combination of both. Below you find some examples:
whois -h whois.denic.de -- -T dn domain

whois -h whois.denic.de "-T dn domain"

whois -h whois.denic.de -- "-T dn domain" 

Error Messages of the DENIC whois Servers

"55000000002 Connection refused; access control limit reached"

To avoid bulk queries to our whois servers and to ensure that the service is available to all users at any time, the number of queries within a defined time interval is limited. If this limit is exceeded, all further queries will be answered with the message "Connection refused; access control limit reached".