1. What is Dynamic DNS?

Dynamic DNS is a method of automatically updating a name server in the Domain Name System, often in real-time, with the active DDNS configuration of its configured hostnames, addresses or other information.

2. I have just deleted my own domain, but I cannot add it again. Why? Can I cancel my removal request?

You must wait for the removal to complete before you can add it again.

DNS Settings

  1. When I register my own domains, which DNS servers should be used?

Please tell the registrar to set the DNS servers to:
ns1.3domain.hk (IP:
ns2.3domain.hk (IP:

  1. Can I use your DNS servers as secondary(slave) DNS servers for my own domains?

No. Our DNS servers should be the sole DNS servers for your own domains.

Software Issues

  1. How can I update my own domain with DynSite?

First, make sure you have the latest version of DynSite.

Then, configure DynSite to use your own domain.

  1. I want to write my own dynamic IP update client program. Could you tell me the update interface specification?

There are two interfaces to choose from. The first one uses standard HTTP protocol (Spec.). The second one uses TCP port 9120, and it is more secure and recommended (Spec. in english, Spec. in japanese).

  1. How to setup and configure a web/email/xxxxx server to work with my domain?

These questions are beyond the support scope. Please find the answer by reading the documentation of your server program.