1. What kind of reverse DNS delegation service does CNNIC provide?
Answer: CNNIC provides reverse DNS delegation service for IP addresses that are allocated by CNNIC. The units for Reverse DNS Delegation are /16 and /24 and the Alliance Member shall apply for the service to obtain it.

2. As for IP addresses that are not allocated by CNNIC, will CNNIC provide reverse DNS delegation service?
Answer: CNNIC can not provide reverse DNS delegation service for IP addresses that are not allocated by CNNIC.

3. Will CNNIC provide reverse DNS delegation for a particular IP address?
Answer: When clients of the Alliance Member require reverse DNS delegation service of a particular IP address from the Alliance Member, The Alliance Member can request us to provide /24 (category C) reverse delegation service after filling in Application Form of Reverse DNS Delegation. After we finish the resolution, the Alliance Member can provide further reverse DNS delegation of the particular IP address to its clients. CNNIC is responsible for providing reverse DNS delegation to the Alliance Member, and the Alliance Member is responsible for providing reverse DNS delegation to its clients.

4. How long will it take to process the application of reverse DNS delegation?
Answer: CNNIC will reply to the Alliance Member after receiving Application Form of Reverse DNS Delegation and inform it of the processing of the application. We will notify the Alliance Member by e-mail within 1 to 2 workdays that the resolution has been finished and ask them to verify the resolution results. If the Alliance Member does not receive any our notification after 2 workdays, please call 010-62619750 and transfer to “IP team of Technology Department”.

5. How to look up whether the reverse DNS delegation has become effective?
Answer: The Alliance Member can use the command subsequent to cmd to look up whether the reverse DNS delegation has become effective.
Take 159.226.6.0/24 for example:
4)nslookup
5)lserver 159.226.1.8
6)6.226.159.in-addr.arpa
If the resolution is successful, the server information will be presented after the commands above are input.