{"uid":"cap_yf3gYafOtrtwXfjewo-UI","slug":"is-port-53-open-7fd63dd4","name":"is-port-53-open","description":"Is TCP port 53 (DNS) open on a host? Attempts a connection from Cloudflare's edge and reports open/closed/filtered with the connect time; Cloudflare-fronted hosts are reported as inconclusive because their edge answers for them. Exposure checks for DNS without running a scanner. $0.01 per check.","url":"https://ip.intel.rallylive.ca/ip/port/53?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","properties":{}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_Sj558ipdbeWGxu39OElW5","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Checks whether TCP port 53 (DNS) is open, closed, or filtered on a given host by attempting a connection from Cloudflare's edge network.","exampleAgentPrompt":"Can you check whether TCP port 53 (DNS) is open on 203.0.113.45? I want to know if that host is exposing its DNS service to the internet without me having to run a scanner.","exampleUseCases":[{"title":"DNS exposure audit on new server","prompt":"We just provisioned a new server at 198.51.100.10 — can you check if port 53 is open on it? I want to make sure we're not accidentally exposing a DNS listener to the public internet."},{"title":"Security check before onboarding a vendor IP","prompt":"Before we allowlist this vendor's IP 203.0.113.77, can you verify whether TCP port 53 is open on it? I need to know if they're running an exposed DNS service."},{"title":"Incident response DNS reachability check","prompt":"We're seeing weird DNS traffic from a client host at 192.0.2.55 — can you quickly check if port 53 is open or filtered on that IP from an external perspective?"}],"resultDescription":"Returns the port status (open, closed, or filtered) for TCP port 53 on the target host, the connection time in milliseconds, and a flag indicating if the result is inconclusive because the host is fronted by Cloudflare's edge (which answers on the host's behalf).","failureModes":["Cloudflare-fronted hosts return inconclusive result because Cloudflare's edge terminates connections","Host or IP unreachable results in filtered/closed status which may be ambiguous","Invalid or non-resolvable hostname causes request failure","Rate limiting or payment failure returns error without port status"],"whenToPreferThis":"Use this endpoint when you need a quick, external-perspective check of whether TCP port 53 (DNS) is reachable on a specific host without deploying your own scanner. It is particularly useful for security audits, infrastructure validation, and incident response where you want to detect DNS exposure from the public internet. Prefer this over general port scanners when you specifically need DNS port visibility with Cloudflare-edge sourcing and a known per-check cost.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-13T00:41:39.331Z","isFirstParty":false,"canonicalSlug":"is-port-53-open-7fd63dd4"}