Q: I have registered a domain name but I cannot lookup my name.  Why?
A: Please check your name servers first.  Moreover, according to RFC1921, if the hostnames of name servers you have filled in are CNAMEs, current BIND implementations will ignore such records.  Please change them to A records instead.

Beware, too, that nslookup by default looks for the A record (IP address) of a domain name.  Do not query our authoritative nameservers (e.g. ns1.cuhk.edu.hk) for the A record of domain names.  Soon they, like the top level domain name servers, will only tell you the NS records, and nothing else.  Therefore, instead of "nslookup foo.com.hk. ns1.cuhk.edu.hk.", use "nslookup -q=any foo.com.hk. ns1.cuhk.edu.hk."

Q: Why do you reject my application when my nameservers are not listed in their NS records?
A: If a nameserver you give us do not list itself as an NS record in the resolution of the domain name you want, then the world will not use it to resolve your domain name, meaning it is not a valid nameserver. In other words, if ns1.foo.net.hk is a nameserver of foo.com.hk, she must have "@ IN NS ns1.foo.net.hk." in her foo.com.hk zone file. If ns2.foo.net.hk is another nameserver, then an additional "@ IN NS ns2.foo.net.hk" record must be served by both ns1 and ns2.foo.net.hk.

A common mistake: ns1.foo.bar is listed in item 7a or 8a of the application form. However, one or both of them serve an NS record saying not ns1.foo.bar, but host1.foo.bar. Even if ns1.foo.bar and host1.foo.bar are different names of the same server, it is still an error we can do without. Please see section 2.8 of RFC1912.

Q: Your reply said "host not found," but our nameservers are working well.  Why?
A: Sorry, "host not found" actually means your nameserver cannot resolve the domain name you want. (It is just the cryptical way the "host" command replies.) To register a domain name, your nameserver must be able to answer queries. More, it must be able to resolve the domain name you want, with authority. For example, if you want domain xyz.com.hk, and your nameserver is ns.pqr.com, make sure "nslookup -q=any xyz.com.hk. ns.pqr.com." gives authoritative answer; otherwise there is really nothing valid for us to register.

Q: My nameservers need to change IP address, and we host many ???.com.hk domain names. Do we need to modify each and every such name?
A: In general, no, you need only to modify the domain name which is part of the name of your nameserver. Technically you need to determine whether the concerned nameserver is a "glue record" of a domain name, and if yes, then you need to modify. The whole story is far too complicated to be explained here. Please read the concept of glue record in some good reference, for example, "DNS and BIND," Cricket Liu, OReilley, or RFC1912.