When configuring custom nameservers, registrars like GoDaddy perform validation checks to ensure:

1. The nameserver hostnames have proper glue records registered with the TLD's registry
2. DNS resolution works end-to-end (forward and reverse)
3. The nameservers are authoritative for the domain

From your examples, the problematic cases reveal important technical constraints:

// This works (correct glue record configuration)
ns1.example.com → 192.0.2.1 (A record exists in parent zone)
ns2.example.com → 192.0.2.2

// This fails (missing glue record)
ns1.example.info → 192.0.2.1 (No A record in .info registry)

Different TLDs enforce varying rules for nameserver registration:

For proper nameserver registration at GoDaddy:

// Sample BIND zone file configuration
$TTL 3600
@ IN SOA ns1.example.com. admin.example.com. (
  2023081501 ; serial
  3600       ; refresh
  900        ; retry
  604800     ; expire
  86400 )    ; minimum

@ IN NS ns1.example.com.
@ IN NS ns2.example.com.

ns1 IN A 192.0.2.1
ns2 IN A 192.0.2.2

Use these commands to verify nameserver setup:

# Check glue records
whois example.com | grep "Name Server"

# Verify DNS resolution
dig +trace ns1.example.com
dig +short NS example.com

# Test authority
dig SOA example.com @ns1.example.com

For dynamic DNS scenarios (like dyndns.org):

• Most registrars reject nameservers with dynamic IPs
• Consider using CNAME flattening if dynamic DNS is required
• Enterprise solutions may require dedicated IPs with proper rDNS

When setting up custom nameservers, three critical components must be properly configured:

• Glue Records: These are A records at the registry level that map your nameserver hostnames (like ns1.yourdomain.com) to IP addresses
• DNS Resolution: The nameservers must be resolvable through normal DNS lookup
• Registry Validation: Some TLDs have additional validation requirements

The cases you mentioned failing reveal important technical nuances:

// Working configuration example (proper glue records)
ns1.example.com. 3600 IN A 192.0.2.1
ns2.example.com. 3600 IN A 192.0.2.2

Versus failing cases:

// Problematic .info configuration
// Many registries require glue records to be set at THEIR level
// Not just in your zone file

For GoDaddy specifically, here's how to properly set up glue records:

// Step-by-step to add glue records in GoDaddy
1. Log in to your GoDaddy account
2. Navigate to Domain Portfolio
3. Click on the domain you want to modify
4. Select "Manage DNS"
5. Under "Hostnames", add your nameserver entries

When encountering "Nameserver not registered" errors:

1. Verify glue records exist at the registry level (not just in your DNS zone)
2. Check TLD-specific requirements (.info has different rules than .com)
3. Ensure proper propagation time (up to 48 hours for some changes)
4. Test DNS resolution from multiple locations

Here's a Python script to verify nameserver registration:

import dns.resolver

def check_ns_registration(nameserver, expected_ip):
    try:
        answers = dns.resolver.resolve(nameserver, 'A')
        for rdata in answers:
            if str(rdata) == expected_ip:
                return True
        return False
    except:
        return False

# Example usage
if check_ns_registration('ns1.example.com', '192.0.2.1'):
    print("Nameserver properly registered")
else:
    print("Registration issue detected")