IPv4 Nameserver Availability

What This Check Does

The IPv4 Nameserver Availability check verifies that at least one of your domain's active nameservers has a valid IPv4 (A record) address. IPv4 remains the dominant protocol for DNS resolution worldwide, and without an IPv4-reachable nameserver, a significant portion of DNS resolvers will be unable to query your domain's DNS records.

DNS Spy queries each of your configured nameservers and confirms that at least one resolves to an IPv4 address. If none of your nameservers have an IPv4 address, this check will fail.

Why It Matters

While IPv6 adoption is growing, IPv4 still handles the vast majority of internet traffic. Many networks, resolvers, and client devices operate exclusively on IPv4. If your nameservers are only reachable via IPv6, you risk making your domain unresolvable for a large portion of the internet. This can lead to website downtime, email delivery failures, and loss of revenue.

Even in dual-stack environments, IPv4 connectivity for nameservers is considered a baseline requirement. Failing to provide IPv4 access is a critical gap in your DNS infrastructure.

Good vs. Bad Configuration

Bad Configuration

Your domain has two nameservers, both with only AAAA (IPv6) records and no A (IPv4) records. Any resolver on an IPv4-only network cannot reach your DNS.

Good Configuration

Your domain has at least two nameservers, each with both A (IPv4) and AAAA (IPv6) records. This ensures maximum reachability across all network types. Example: ns1.example.com resolves to both 198.51.100.1 and 2001:db8::1.

How DNS Spy Monitors This

DNS Spy continuously checks the DNS records for each of your nameservers. When this check runs, it resolves the A records for every active nameserver and verifies that at least one valid IPv4 address exists. If all nameservers lack IPv4 addresses, DNS Spy triggers an alert so you can correct the issue before it impacts your users. Monitoring runs at regular intervals to catch any changes to your nameserver configuration.