I am bit confused with where "Glue record" is used in DNS.
This documents say
If you are using someone else's name servers (eg. your ISP's), you won't need to worry about glue records. You only need to worry about glue records when you are configuring your own name servers where a circular reference exists.
Glue record will be present only for nameservers which are within the domain for which they are authoritative for. i.e they are required if example.com has nameserver as ns1.example.com and it will not be required if it is on another domain.
Based on this document I use
dig command to see if glue records are present for domains which have nameserver hosted in another domain. And surprisingly they too have glue records !. I am trying to see if
novanext.com has glue record as their nameservers are in different domain.
$ dig ns com. ;; ANSWER SECTION: com. 85916 IN NS j.gtld-servers.net. com. 85916 IN NS f.gtld-servers.net. com. 85916 IN NS i.gtld-servers.net. com. 85916 IN NS g.gtld-servers.net. ....
And next getting the "glue" record of
$ dig ns novanext.com @g.gtld-servers.net. ; <<>> DiG 9.8.4-rpz2+rl005.12-P1 <<>> ns novanext.com @g.gtld-servers.net. ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 55040 ;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 6 ;; WARNING: recursion requested but not available ;; QUESTION SECTION: ;novanext.com. IN NS ;; AUTHORITY SECTION: novanext.com. 172800 IN NS ns2.net4india.com. novanext.com. 172800 IN NS ns1.net4india.com. ;; ADDITIONAL SECTION: ns2.net4india.com. 172800 IN A 18.104.22.168 ns2.net4india.com. 172800 IN A 22.214.171.124 ns2.net4india.com. 172800 IN A 126.96.36.199 ns1.net4india.com. 172800 IN A 188.8.131.52 ns1.net4india.com. 172800 IN A 184.108.40.206 ns1.net4india.com. 172800 IN A 220.127.116.11 ;; Query time: 279 msec
How is this possible ? I have googled a lot but still not able to figure it out. Any help will be appreciated.