Introduction

The Domain Availability Checker (DAC) is available to Nominet registrars who are also members. The service includes two DAC tools enabling you to make high volumes of queries about the availability of domain names.

The DAC services are high volume query tools that return a limited amount of data to the requester. They run on secondary copies of the register that are updated by an immediate replication process. The DAC tools only return information on .uk domain names operated by Nominet and not second level domains operated by other parties (eg. .ac.uk)

The DAC tools

Subscription to the DAC will provide access to both of our DAC tools:

• Real time DAC: This service operates in real time and returns a limited set of data about the domain name being queried. Access limits are set at a flat rate for all subscribers.
  
• Time delay DAC: This service operates with a 100ms delay and returns a larger set of query data. Access limits are dependant on the subscribers business levels.
  

Eligibility

Access to our Domain Availability Checker (DAC) tools is restricted to registrars who also have Nominet membership. The services are available on a subscription only basis.

Fees

The DAC service will be charged at £25 + VAT per year. This fee will be charged to your credit account. The single subscription fee gives access to both the real time DAC and the time delay DAC. 

How to apply

To apply for access to our DAC services please use the application form which is under the new services tab in your online service account.

You will also be required to confirm that you accept the Terms and Conditions of the DAC contract.

Usage

Clause 5.2 of the contract sets out how you can use the DAC, and limits of use are set out in the contract (particularly clause 5.3) and in the acceptable use polices for each tool (simply called the 'policy' in the contract). 

The main scenarios where we would expect users to use the DAC are:

• Where a potential registrant has enquired whether a specific domain name is available for registration;
• If a domain name is not available for registration, querying a number of similar domains to determine if they are available so that they could be offered as alternatives to the potential registrant;
• For those seeking to determine whether domain names which have been in a suspended state have become available for registration.

However, any activity not prohibited by the contract terms is permitted.

Why do we have two DAC services?

The services are provided to enable a high volume of lookups to registrars to help their customers find appropriate domain names for registration. This allows registrars to provide services such as suggesting available alternatives or complementary domain names. This type of service requires a high volume of look ups to be performed to meet a single customer request.

A single DAC service could not support high volumes to all users. By providing two services and moving non-time critical queries to the time delay DAC, the load on the real time DAC will be reduced. The small delay is not noticeable for customer facing domain query services.
 
The provision of two versions of the DAC meets the needs of all of our customers, whilst ensuring that no customer group suffers a decrease in access levels. The two different versions of the DAC complement each other and support a variety of different registrar business models. We will monitor DAC usage, capacities and performance and consider further changes to access limits as appropriate.