Domain Check (Whois-is)

Tells you whether or not a particular domain name can be registered

You should use Domain Check if you wish to provide a search function for .ch and .li domain names on your website or in your web application.
Like the Whois service, Domain Check tells you whether a particular domain name is still available or already registered. Unlike Whois, however, it does not display any contact details for domain names that are already registered. As a result, Domain Check places a much more generous limit on the number of searches. This service was designed for automated searches. It delivers results that can be read on screen or by a computer.

Domain Check runs on the host using port 4343. You can use these details to integrate the Domain Check search function into your web application. If you use a Whois client, it should allow you to specify a port.

Example of a Domain Check search:

whois -h -p 4343

-h = host (

-p = port (4343)

A Domain Check reply looks like this:

<Reply-Code> : <visually-readable reply>


0: This domain name can not be registered.
Reason: This domain name is already registered.

The visually-readable reply can be divided up over different lines.

The following reply codes are currently specified:


Domain name can be registered


Domain name cannot be registered


Invalid enquiry (i.e. modify enquiry prior to next attempt)


Access restricted (i.e. wait a while and then try again)


Temporary server error (i.e. wait a while and then try again)

NB: The visually-readable answer sequences (strings) can be changed without prior notice. It is thus not advisable to use them in automated software.