{"uid":"cap_0J-k-E2MDvdiAU6dfDpWD","slug":"reverse-dns-via-mullvad-b0c7f35f","name":"reverse-dns-via-mullvad","description":"Reverse DNS (PTR) of an IPv4 address as answered by Mullvad DNS: the hostname(s), TTL and response code, plus whether the PTR's forward A record points back (forward-confirmed reverse DNS). Compare resolvers for stale or filtered answers. $0.01 per lookup.","url":"https://ip.intel.rallylive.ca/ip/ptr/via/mullvad?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$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_4O2CJKU6-hJqrUO8p9Iyq","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":"Performs a reverse DNS (PTR) lookup for an IPv4 address using Mullvad DNS and verifies forward-confirmed reverse DNS (FCrDNS)","exampleAgentPrompt":"Look up the reverse DNS PTR record for 185.220.101.45 using Mullvad's resolver and tell me if it's forward-confirmed — I want to see the hostname, TTL, response code, and whether the A record points back.","exampleUseCases":[{"title":"Verify mail server PTR record","prompt":"Check the reverse DNS for 209.85.167.54 through Mullvad DNS — I need to know the PTR hostname, whether it's forward-confirmed, and what response code came back, so I can validate this mail server's rDNS setup."},{"title":"Detect stale or filtered PTR via alternative resolver","prompt":"Pull the PTR record for 1.1.1.1 using Mullvad's DNS resolver and tell me if it's stale or filtered compared to what you'd expect — include the TTL and FCrDNS result."},{"title":"Investigate suspicious outbound connection IP","prompt":"I'm seeing outbound connections to 45.33.32.156 and want to know its reverse DNS hostname as seen by Mullvad DNS, whether the PTR is forward-confirmed, and what the TTL is."}],"resultDescription":"Returns the PTR hostname(s) associated with the queried IPv4 address as resolved by Mullvad DNS, along with the TTL, DNS response code (e.g. NOERROR, NXDOMAIN), and a boolean indicating whether the PTR's forward A record resolves back to the original IP (forward-confirmed reverse DNS / FCrDNS).","failureModes":["NXDOMAIN returned if no PTR record exists for the IP","Mullvad DNS may return filtered or censored responses for certain IPs","FCrDNS check fails if the PTR hostname has no forward A record","Network timeout if Mullvad resolver is temporarily unreachable","Invalid IPv4 input returns an error or unexpected result"],"whenToPreferThis":"Choose this endpoint when you specifically want to see how Mullvad's DNS resolver answers a PTR query — useful for comparing resolver behavior, detecting filtered or censored DNS responses, or validating FCrDNS from a privacy-focused resolver's perspective rather than a generic public resolver.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-11T18:43:39.015Z","isFirstParty":false,"canonicalSlug":"reverse-dns-via-mullvad-b0c7f35f"}