Unraveling the DNS Dilemma: GRC Benchmark Quirks Explained


“Why does the GRC DNS Benchmark test indicate that my DNS servers are unresponsive when I use my ISP’s DNS servers through the default gateway (, despite all other functions operating normally? However, when I switch to public DNS servers like,, or, or even input my ISP’s DNS servers in custom mode, the benchmark test proceeds without issues. This occurs with my Calix 844 router. What could be the reason for the GRC Benchmark test failing only in the default gateway mode with set as the DNS?”


When conducting a DNS benchmark test using tools like GRC’s DNS Benchmark, users may encounter a perplexing scenario where their Internet Service Provider’s (ISP) DNS servers appear unresponsive in the default gateway mode, yet function normally for everyday internet activities. This discrepancy becomes even more puzzling when switching to public DNS servers or entering ISP DNS servers in custom mode results in successful benchmark tests. To unravel this mystery, particularly in the context of a Calix 844 router, we must delve into the intricacies of DNS server configuration and the benchmarking process itself.

The default gateway provided by an ISP typically serves as a local DNS proxy rather than a direct DNS server. This means that DNS queries are first routed through the gateway ( before reaching the actual DNS servers. In default mode, the benchmark tool may misinterpret this proxy behavior as a lack of response, especially if the proxy delays the forwarding of DNS queries or if the benchmark tool does not account for the additional hop in the network.

Public DNS Servers and Custom Mode

Public DNS servers like (Cloudflare), (Quad9), and (Google) are designed to be directly accessible and optimized for quick responses. When these servers are used, or when ISP DNS servers are manually entered in custom mode, the DNS queries bypass the local DNS proxy, eliminating any potential delays caused by the default gateway. This direct approach is likely recognized by the benchmark tool, which then proceeds with the test without issues.

Router Specifics: Calix 844

The Calix 844 router, like many others, may have its own DNS handling mechanisms that could affect benchmark results. Routers often implement features to enhance network performance or security, which might interfere with the benchmark tool’s ability to accurately assess DNS server responsiveness.


The GRC DNS Benchmark test’s indication of unresponsive DNS servers in default gateway mode can be attributed to the local DNS proxy mechanism, router-specific DNS handling features, and the benchmark tool’s testing methodology. To ensure accurate benchmark results, users may consider using public DNS servers or manually configuring their DNS settings in custom mode. It’s also advisable to consult with the ISP or router manufacturer for detailed insights into the router’s DNS management and to explore any available firmware updates that might address such anomalies.

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