I will be quite detailed.
sme1 is on an RFC1918 network (I know all about rfc1918, I was one of the authors) and running as domain test.htt-consult.com.
onlo.htt-consult.com is the master DNS server for htt-consult.com; onlo is a Centos 5 system. As such, onlo will have in the htt-consult-zone file records to delegate test.htt-consult.com to sme1.test.htt-consult.com and I will have to have a glue record so that this is resolvable within this zone file (you are not suppose to put an IP address in an NS RR, so you get these glue problems in delegations).
At this point, if medon.htt-consult.com that uses onlo.htt-consult.com as its DNS server, needs to access URL
http://www.test.htt-consult.com, it will query onlo which will return that sme1 is authoritative for test.htt-consult.com. medon will then query sme1 (that is the way it should work) and get 192.168.128.12 as the IP address of the URL.
Fine. It SHOULD work, and I hope to have this setup later today....
[oops, onlo can query sme1 itself, and return the IP information and cache this result for later use. This is frequently the way things are done, and can result in some fun cache poisoning situations]
But additionally, I would like onlo to be a secondary server for the zone test.htt-consult.com. This is very standard DNS stuff, but care has to be taken if the zone in question is updated via DYNDNS.
So to setup a secondary DNS, there are two steps:
On the primary you add an NS record for the secondary server, and you setup a notify to that server so it gets the changes pushed to it, rather than having to pull.
On the secondary, you define the zone and create the file(s) where the zone information will be stored.
So for sme, I have to be able to add this second NS record into the test.htt-consult.com zone file, and I have to specify it to notify onlo of any changes.
Is that clearer than typical DNS mud?
BTW, although I have been configuring BIND since '93, I tend to use webmin. I frequently make changes 'by hand' but just as often use the webmin BIND tool. When you only make DNS changes once every few months, you have to think: 'Now how do I do that again'.