prebensen.com

What It Is

This site provides an RFC 8914 Extended DNS Errors (EDE) testbed, designed to verify how EDE information propagates across real networks from authoritative DNS servers, resolvers, forwarders, and finally to clients. It is more of a protocol testing infrastructure than a general-purpose developer tool. Users can query specific domains with dig and inspect the returned DNS status, EDE code, and EXTRA-TEXT.

Core Features and Ecosystem

The testbed supports three query formats: <label>.nx.ede.dn5.dk returns NXDOMAIN, <label>.cname.ede.dn5.dk returns CNAME, and <label>.addr.ede.dn5.dk returns A/AAAA records. The label can be replaced with tags such as blocked, censored, or filtered, or with a numeric code directly. The page lists multiple EDE error codes from 0 to 30, covering scenarios such as DNSSEC, filtering, network errors, and policy restrictions. The article also discusses the relationship between EDE and DNS filtering, RPZ, STOP pages, and browser error messages, and mentions related ecosystem tools and projects such as dnsdist, Unbound, RIPE Atlas, and CannedDNS.

Pricing and Openness

The page does not mention commercial pricing, accounts, plans, or payment methods, so it can currently be understood as a public testing resource. The article refers to a “git repo for this testbed,” but does not clearly state a license, so its full open-source status cannot be determined. For self-hosting, the only clear information is that CannedDNS has been extended into an authoritative DNS server capable of serving this testbed; deployment steps are not provided.

Pros and Cons

Its strengths are its highly focused purpose and its query method based on standard DNS tools, making results easy for developers to reproduce. It also covers a broad range of error codes and closely relates to DNS filtering and end-user usability issues. Its drawbacks are that the documentation reads more like research notes, with no Web UI, API, SDK, automated reporting, or complete deployment guide. In addition, test results can be affected by public resolvers and local network paths.

Who It’s For and Access from China

It is suitable for researchers and developers working on DNS resolvers, forwarders, filtering products, browser networking stacks, and network measurement. The article does not mention access from China, and domain/DNS query availability may also be affected by local network conditions and resolver policies, so this is marked as unknown. Alternatives include building your own authoritative DNS test environment, or combining tools such as dig, dnsdist, Unbound, and RIPE Atlas for custom measurements.