Creating glue records with bind 9

It's not pretty. Basically, you have to create a zone with the exact name of your name servers. Even if one of those name servers are probably controlled by your ISP. Even if you already have an A record for your local NS

In the following examples, ns1.example.com is your primary name server, sdns1.isp.com is the secondary name server your ISP is letting you use.

Add the following to /etc/named.conf:

zone "ns1.example.com" {
        type master;
        file "master/ns1.example.com.zone";
};

zone "sdns1.isp.com" {
        type master;
        file "master/sdns1.isp.com.zone";
};

This is master/ns1.example.com.zone:

$TTL 300
@               IN      SOA     ns1.example.com. root.example.com. (
                                2017042702                      ; yymmdd##
                                2h                              ; Refresh
                                1h                              ; Retry
                                2W                              ; Expire
                                1h                              ; Minimum
                        )
                IN NS   ns1.example.com.
                IN NS   sdns1.isp.com.

@               IN A 1.2.3.4  // change this to the real IP

This is master/sdns1.isp.com.zone:

$TTL 300
@               IN      SOA     ns1.example.com. root.awale.qc.ca. (
                                2017042702                      ; yymmdd##
                                2h                              ; Refresh
                                1h                              ; Retry
                                2W                              ; Expire
                                1h                              ; Minimum
                        )
                IN NS   ns1.isp.com.
                IN NS   ns2.isp.com.

@               IN A 4.3.2.1 // change this to the real IP of sdns1.isp.com

Get the real IP of sdns1.isp.com with

host sdns1.isp.com
sdns1.isp.com has address 66.51.199.62

You can find the NS records for sdns1.isp.com with

# dig NS isp.com
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.62.rc1.el6_9.1 <<>> NS isp.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30596
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 2

;; QUESTION SECTION:
;isp.com.   IN NS

;; ANSWER SECTION:
isp.com.  7200 IN NS ns2.isp.com.
isp.com.  7200 IN NS ns1.isp.com.

;; ADDITIONAL SECTION:
ns2.isp.com.  172799 IN A 66.51.206.98
ns1.isp.com.  172799 IN A 66.51.202.50

;; Query time: 210 msec
;; SERVER: 10.0.0.2#53(10.0.0.2)
;; WHEN: Thu Apr 27 16:10:12 2017
;; MSG SIZE  rcvd: 93