How do dark.fail and checkitonion verify .onion uptime and how reliable are their methods?
Executive summary
Dark.fail publicly combines curated, PGP-verified .onion addresses with automated availability checks and mirror lists to show whether a hidden service is reachable, but its scope is selective and it reports availability — not a security or authenticity guarantee — so its uptime readings are useful but imperfect [1] [2] [3]. Reporting on "checkitonion" could not be located in the supplied materials, so any claims about that service are outside the evidence reviewed here (no source).
1. What dark.fail does and how it measures uptime
Dark.fail operates as a curated directory of notable Tor hidden services and publishes both PGP-verified addresses and an uptime status for listed sites and their mirrors, presenting uptime history and current reachability for each entry [1] [4] [5]. The site emphasizes PGP verification of addresses — providing signed data and a PGP tool — as part of its model to reduce phishing and address-typos, while its pages expose whether a given .onion responds over Tor and list alternative mirrors when available [1] [6]. Independent coverage describes dark.fail as monitoring a limited but top-tier selection of onion sites and notes explicitly that it monitors availability only, not site safety or security posture [2].
2. The technical approaches implied by public documentation
Public-facing descriptions and community writeups indicate dark.fail’s status display is generated by automated checks that attempt to access each .onion and record reachability and historical uptime; the project’s GitHub and site describe the purpose as “check whether a .onion site is online” and to “view the uptime history” of popular Tor sites and their mirrors, which implies periodic Tor-proxied requests and recording of successes and failures [4] [1]. Broader technical guides and tooling for onion uptime — including self-hosted Nagios-like solutions and cloud onion-checkers referenced in community sources — show the two common approaches: run Tor-aware probes from one or more monitoring endpoints, or use proxied/cloud browsers that can access .onion addresses without a local Tor client [7] [8] [9]. Those methods illuminate what dark.fail likely does at scale: scheduled Tor connections from monitoring nodes and aggregation into an uptime timeline [4] [1].
3. How PGP verification factors into reliability
PGP verification is dark.fail’s principal defense against fake links and phishing: by publishing signed listings and offering a tool to verify signatures, dark.fail gives users a cryptographic chain-of-trust to check that an onion address matches an operator’s known key rather than relying solely on an easily spoofed plaintext link [1] [10]. Security guides in the community explicitly recommend verifying market PGP keys (for example via /pgp.txt on the target site) and cross-checking with multiple sources including dark.fail, underlining that signature checks reduce one class of risk even if they don't prove uptime or server integrity [10] [11].
4. Where uptime signals can mislead — limits and failure modes
Uptime as reported by a checker is a blunt signal: it tells whether a service responded to the probe, not whether the site is uncompromised, authentic beyond its signed address, or functionally healthy for users — a limitation dark.fail and independent writeups note explicitly [2] [1]. Tor’s transient routing, guard node churn, regional blocking, or probe placement can produce false negatives or intermittent readings that reflect network conditions rather than server-side outages, and single-location probes are vulnerable to local connectivity issues unless the monitor runs multiple, distributed exit/egress points [2] [7] [9]. Community posts from archival/directories praise dark.fail for reducing phishing risk and tracking downtime that sometimes correlates with takedowns or DDoS, but they also warn that downtime signals are noisy and must be interpreted cautiously [11] [3].
5. Verdict on reliability and recommended practices
Dark.fail is reliable as a curated, conservative indicator of whether a popular .onion is reachable and whether an address matches a PGP-signed listing, but its coverage is selective and its uptime metric should be treated as "connectivity observed from the project’s probes," not as an authoritative forensic statement about the service’s security or global accessibility [1] [2] [4]. Best practice — recommended by community guides and reinforced by dark.fail’s own emphasis on verification — is to combine PGP signature checks, multiple independent probes or monitoring tools (self-hosted Tor-aware monitors or cloud onion browsers), and cross-referencing with other reputable directories before concluding a site is authentic and available [10] [7] [8]. No verifiable documentation for a separate service named "checkitonion" was present in the supplied reporting, so its methods and reliability cannot be assessed from these sources (no source).