{"uid":"cap_gpVsOtvhi9aGcRmYpE8t0","slug":"is-port-139-open-d01bf756","name":"is-port-139-open","description":"Is TCP port 139 (NetBIOS) 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 NetBIOS without running a scanner. $0.01 per check.","url":"https://ip.intel.rallylive.ca/ip/port/139?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$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_kQE-xmfm7cTHbiHhOsdyv","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 139 (NetBIOS) is open, closed, or filtered on a given host by attempting a connection from Cloudflare's edge network.","exampleAgentPrompt":"Can you check if TCP port 139 (NetBIOS) is open or closed on the host 203.0.113.45 — I want to know if it's exposed to the internet without me having to run a scanner.","exampleUseCases":[{"title":"Firewall audit after hardening","prompt":"I just updated the firewall rules on 198.51.100.10 to block NetBIOS — can you verify that port 139 is now closed from the outside?"},{"title":"Security exposure check on new server","prompt":"Before I put this server at 203.0.113.22 into production, can you check whether TCP port 139 is open or filtered from the internet?"},{"title":"Incident response NetBIOS check","prompt":"We got an alert about possible NetBIOS exposure — can you quickly check if port 139 is open on 192.0.2.88 and how fast it responds?"}],"resultDescription":"Returns a status of open, closed, or filtered for TCP port 139 on the target host, along with the connection time in milliseconds. If the host is behind Cloudflare's edge, the result is marked inconclusive because Cloudflare's infrastructure answers on behalf of the origin.","failureModes":["Host is Cloudflare-fronted — result returned as inconclusive rather than open/closed","Host unreachable or DNS resolution failure — may return filtered or an error","Firewall silently drops packets — may report filtered rather than closed","Rate limiting or payment failure — check rejected before execution","Invalid hostname or IP format — request rejected"],"whenToPreferThis":"Use this endpoint when you need a quick, lightweight check of NetBIOS port 139 exposure from an external vantage point (Cloudflare's edge) without deploying a network scanner. Ideal for security audits, compliance checks, and post-firewall-change verification on individual hosts. Prefer this over general-purpose port scanners when you specifically need NetBIOS exposure confirmation via a pay-per-use API with no setup.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-13T00:41:35.586Z","isFirstParty":false,"canonicalSlug":"is-port-139-open-d01bf756"}