During DNS resolution, a common anti-pattern emerges when administrators attempt to alias nameservers using CNAME records. Consider this problematic configuration:

; INVALID CONFIGURATION
subdomain.example.com.       IN NS  ns1.example.com.
ns1.example.com.             CNAME  foo.example.com.
foo.example.com.             IN A   10.1.1.1

The DNS protocol explicitly prohibits this practice in RFC 2181 Section 10.3:

"The domain name used as the value of a NS resource record, or part of the value of a MX resource record must not be an alias. Not only is the specification clear on this point, but using an alias in either of these positions neither works as well as might be hoped, nor well fulfills the ambition that may have led to this approach."

Modern DNS servers implement this restriction differently:

• BIND 9: Logs "NS points to CNAME" errors
• PowerDNS: Rejects such configurations during zone loading
• Windows DNS: Silently drops the CNAME resolution

Instead of CNAME indirection, use these approaches:

; METHOD 1: Direct NS to A record
subdomain.example.com.       IN NS  foo.example.com.
foo.example.com.             IN A   10.1.1.1

; METHOD 2: Use multiple A records
subdomain.example.com.       IN NS  ns1.example.com.
subdomain.example.com.       IN NS  ns2.example.com.
ns1.example.com.             IN A   10.1.1.1
ns2.example.com.             IN A   10.1.1.2

The DNS protocol requires immediate resolution of NS records during delegation. CNAMEs would require:

1. Additional resolution steps
2. Potential circular references
3. Increased latency during zone transfers

When troubleshooting, use these commands to verify proper NS setup:

dig +trace example.com NS
dig +short example.com NS
named-checkzone example.com /etc/bind/db.example.com

Some administrators attempt these problematic solutions:

; ANTI-PATTERN: Using DNAME (equally invalid)
ns1.example.com.             DNAME  foo.example.com.

The only RFC-compliant solution remains using direct A/AAAA records for nameserver targets.

In DNS implementations, having an NS record point to a CNAME (Canonical Name) record violates RFC standards and causes operational issues. The key reasons:

• RFC 1034 Section 3.6.2 explicitly states: "NS records pointing to CNAMEs is a configuration error"
• RFC 2181 Section 10.3 further clarifies: "CNAMEs must have no other resource records of other types"

Here's why the following configuration fails:

subdomain.example.com.       IN NS  ns1.example.com.
ns1.example.com.             CNAME  foo.example.com.
foo.example.com.             IN A   10.1.1.1

While this valid alternative works:

subdomain.example.com.       IN NS  foo.example.com.
foo.example.com.             IN A   10.1.1.1

Major DNS servers handle this differently:

For cases where you need indirection:

; Preferred method using A/AAAA records directly
subdomain.example.com.       IN NS  ns1.foo.example.com.
ns1.foo.example.com.         IN A   10.1.1.1

; Alternative with glue records when necessary
example.com.                 IN NS  ns1.cloudprovider.net.
ns1.cloudprovider.net.       IN A   203.0.113.45

When troubleshooting NS-CNAME issues:

1. Use dig +trace to follow the resolution chain
2. Check with delv for DNSSEC validation failures
3. Test with multiple resolvers (1.1.1.1, 8.8.8.8, etc.)