Will setting lower TTL on name server (NS) records cause the TTLs on other records to lower?

Solution 1:

In the DNS context, a TTL defines the duration that a resource record (RR) may be cached by any resolver.

NS RRs are part of what is sometimes called the zone's infrastructure records. Infrastructure RRs (which include SOA, NS and MX RRs) are unique in that they return other names not addresses, as such they should be stable and to minimize DNS access can and should have very long TTLs (days and weeks).

You specify a TTL for a certain RR if you want to override the default value.

Based on your records configuration;

Upon the first recursion of a resolver:

Each NS record will be cached for 1 hour, and test.example.com will be cached for 4 hours.

Say after 30 minutes the same resolver has been asked for test.example.com record, the cached one will be returned without contacting your authoritative NS.

Say after 120 minutes the same resolver has been asked for test.example.com record, the cached one will be returned without contacting your authoritative NS.

But at this point if the resolver is asked about foo.example.com, it will have to do a new recursion to find your NS RR, then find foo.example.com.