This question already has an answer here:
Whenever we register a new domain name from a Registrar, we need to tell them what is the nameserver by providing them the dns server IP address.
But in the same time in the zone file of our dns server (I will use bind9 in this case), we also add the RR like the following:
abc.net. IN NS ns1.abc.net. abc.net. IN NS ns2.abc.net.
which is the authoritative record.
1)So what is the purpose of having the authoritative record of
NS in the zone file of
abc.net, since when one trying to resolve let say
www.abc.net, the TLD
.net already tell us they are in
2)Since from the delegation concept point of view,
NS record only need to be stored in the parent of the zone, meaning root server NS tell us NS of
.net server NS tell us the NS of
.abc.net NS resolve the dns query. so in order to resolve
www.abc.net, there are only 3 set of NS IP address we need to know:
- root server NS that tell us where is
.it...etc. root server NS IP is store in bind9
.netNS that tell us where is
.netNS IP is stored in root server NS record.
.abc.netNS that tell us where is
.abc.netNS IP is stored in
- so since we don't have any
www.subdomain.abc.net, we shouldn't need to store any NS record for
.subdomain.abc.net, isn't it ?
3)What will happen if I don't put the
NS record of
abc.net in my
abc.net zone file ?
4)What if I have
NS record in my zone file but not in the Registrar? which one will be the resolver take ?
There are a detail answer here, but I still don't understand the meaning behind it.