• What does the DAC service include?
• What can I use the DAC for?
• What are the two DAC tools?
• Why do you have two DAC tools?
• Who is eligible to use the DAC?
• Can I use both DAC tools?
• How much does it cost?
• How do I apply?
• How long does the application process take?
• When does the contract begin?
• How up to date is the DAC?
• What information is returned about a domain name being queried?
• How many queries can I make?
• What happens if I exceed the query limits?
• Are the query limits for each DAC tool ever combined?
• Do I have to wait for a reply to my previous query before I send another query?
• How do I connect to the DAC?
• What happens when I make a new connection?
• Can I leave my connection to the DAC open all day?
• How many simultaneous connections can I have?
• How do I notify you of a change of IP address or if my contact details have changed?
• How do I unsubscribe?
• What happens if I resign my membership or my account is suspended?
• Who can I contact for help?

What does the DAC service include?
The DAC service includes two DAC tools enabling you to make high volumes of queries about domain names.

What can I use the DAC for?
The main reasons for using 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 have become available for registration
  

What are the two DAC tools?
The two DAC tools are:

• 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 subscriber’s business levels.
  

Why do you have two DAC tools?
By providing two services, non-time critical queries can be moved to the time delay DAC and the load on the real time DAC can be reduced. The two different versions of the DAC complement each other and support a variety of different registrar business models.

Who is eligible to use the DAC?
The DAC is available to Nominet registrars who are also members.

Can I use both DAC tools?
Yes, subscription to the DAC gives access to both of our DAC tools.

How much does it cost?
The DAC service is charged at £25 + VAT per year.  The first year’s fee is payable upon application, whilst fees for subsequent years will be charged to your credit account.

How do I apply?
You can apply for access to the DAC through your online service account under the new services tab.

How long does the application process take?
The application process takes 2 - 3 working days.

When does the contract begin?
Your contract begins on the day that we tell you that your application to use the DAC has been accepted. It continues indefinitely unless it is terminated or suspended under the contract terms.

How up to date is the DAC?
The real time DAC responds in real time with a limited amount of information about the domain name being queried.

The time delay DAC returns data with a 100ms delay.

What information is returned about a domain name being queried?
The data returned for the real time DAC is:

• Domain name
• Registered flag (Y/N only)
• Detagged flag
• Registration date
• Renewal date
• TAG

The above data is also returned for the time delay DAC, with the addition of:

• Suspended flag
• Registration status
  

How many queries can I make?
Access to the real time DAC is provided at a flat rate for all subscribers. Full details are provided in the real time DAC acceptable use policy

Access to the time delay DAC is dependant on the subscriber’s business levels and uses a formula. Full details are provided in the time delay DAC acceptable use policy

What happens if I exceed the query limits?
If you exceed the query limits, a block will be imposed. You will know when this has happened because the DAC will respond to the first blocked query with:

<domain-name>,B,<delay>

where:
<domain-name> is the domain name that caused the client to exceed quota
B indicates that the connection is now blocked
<delay> is the delay in seconds until the block is cleared

Are the query limits for each DAC tool ever combined?
No, the query limits for real time and time delay DAC are independent of each other.

Do I have to wait for a reply to my previous query before I send another query?
There is no need to wait for a response before sending another request. Both the real time DAC and the time delay DAC will add any further requests to a queue and respond in turn.

How do I connect to the DAC?
The real time DAC is available to TCP connections on port 3043 at dac.nic.uk from registered IP addresses only.

The time delay DAC is available to TCP connections on port 2043 at dac.nic.uk from registered IP addresses only.

What happens when I make a new connection?
Each time you make a new connection to either the real time or the time delay DAC, there is a pause of 3 seconds before starting the service. Both DAC tools are designed to support long standing connections, not large numbers of repeated connections and disconnections.

Can I leave my connection to the DAC open all day?
Yes, you can. However the connection will be closed if there have been no queries for a 60 minute period. You should also switch on TCP KEEP_ALIVE with an interval of less than 15 minutes.

How many simultaneous connections can I have?
You are limited to a maximum of four simultaneous connections from registered IP addresses. This can mean one from four different IP addresses or four from the same IP address.

If a new connection is made and exceeds the limit of four simultaneous connections, the oldest connection will be dropped.

How do I notify you of a change of IP address or if my contact details have changed?
If you need to change your IP address or your contact details, you can do this through your online service account.

How do I unsubscribe?
If you no longer want to subscribe to the DAC service, you should send us a secure message from your online service account. Alternatively you can send a PGP signed email to our Member and Registrar Support team at support@nominet.org.uk.

What happens if I resign my membership or my account is suspended?
Your DAC contract will terminate automatically if you resign your membership. It will also terminate if your tag is cancelled or if your membership or registrar agreement ends for any other reason.

Who can I contact for help?

• For general support enquiries, please contact Member and Registrar Services on + 44 (0) 1865 332233 or email support@nominet.org.uk
• For technical enquiries, please contact the Technical Support team on +44 (0) 1865 332211 or email hostmaster@nominet.org.uk

Support for the DAC is only available during office hours. It is not covered by our out of hours support service.