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Custom nameservers

using your own nameserver to point to another DNS control panel

1and1 does not do custom nameservers.

Enom does.

Dreamhost domain management also allows custom nameservers.

Most Drupal shops point their own DNS at their hosts:
Lullabot, Palantir, DevSeed uses http://networkredux.net/

Acquia is using http://www.nettica.com/

Notes:
(lost the links these came from)

"create two sub domains for your domains and explicitly assign A records to them. Afterwards, enter these two sub domains as name servers for your domain. This will create the required name server records."

can i point an ns subdomain to another nameserver IP DNS

A (Host) - Links a Name to an IP Address

CNAME (Alias) - Links a Name to another Name. It has some restrictions on usage, you can't have a CNAME Record share a Resource with any other record type (including itself).

NS (Name Server) - States which Servers can answer authoritatively for a given Domain

Onto Sub-Domains...

Subdomains can have A Records and NS Records. NS Records only state responsibility for a specific name, they don't give you an answer that you can use in a Web Browser at all.

For the Browser you would need either a CNAME (Alias) or A (Host) for it to work. In which case you might have:

www.domain.com. A 192.168.1.1
subdomain.domain.com. NS
subdomain.domain.com. A 192.168.1.1
www.subdomain.domain.com. CNAME subdomain.domain.com.

The thing is, you don't need the NS Record unless you're delegating responsibility for the Sub-Domain elsewhere. And if you were you wouldn't have the A Record as well (if that all makes sense).

So you could simply have:

www.domain.com. A 192.168.1.1
subdomain.domain.com. A 192.168.1.1
www.subdomain.domain.com. CNAME subdomain.domain.com.

Remember the limitation on CNAME mentioned above? That's the only reason you can't have:

www.domain.com. A 192.168.1.1
subdomain.domain.com. NS
subdomain.domain.com. CNAME www.domain.com.
www.subdomain.domain.com. CNAME www.domain.com.

Even if we don't have that NS Record there it's implied and can get a bit upset if you try and create a CNAME on the same level.

So...

To set up a new Sub-Domain you can add an NS Record, and that should point to the current Name Server (as that's the one answering the question). And you must add a Host (A) Record so it resolves the name to an IP.

Reference

http://www.ntchosting.com/dns/dns-records.html