Can an IP address be used as a name server?

[Kolusion]

I host my website domain1.com on 12.34.56.78.
I currently use my registrars DNS server to point to my server on 12.34.56.78.
I have established a DNS server on 12.34.56.78

I try to add '12.34.56.78' to the domains NS records with my registrar, but my entry '12.34.56.78' is rejected.

Is it wanting me to add something like ns1.domain1.com? I don't see how this is going to work as a name server lookup will be required for ns1.domain1.com in the first place.

[Irithori]

You cannot enter an IP as a DNS while domain registering.
It needs to be a NameServer Rssource Record, which is a hostname. Not a IP.
For this hostname, you need a A record to resolve it to an IP.

In case the NS-RRs (Most registrars require at least two to register) are within the domain,
glue records will be added to the top level domain server, as well as the delegation records.

[Kolusion]

None of this is making ant sense to me.

You say a NameServer Resource Record has to be a hostname, then how does my registrar restrar1.com use their own domain as a DNS server?

[Kolusion]

Ahhh.. so a 'glue record' hey.. No problem. Thanks!