IP Lookup — Geolocation, ASN & Reverse DNS
The dnsverifier.com IP Lookup tool accepts an IPv4 / IPv6 address, a domain name, or a URL — domains are resolved via A / AAAA before lookup — and returns a complete intelligence sheet: reverse DNS with forward-confirmed match check, geolocation (country, region, city, lat/lng, timezone, ISP, hosting/proxy/mobile flags), ASN and AS name via Team Cymru's public DNS service, RIR-level WHOIS for the registered network, DNSBL scan across 9 major blocklists, and cloud-provider detection against AWS, GCP, Cloudflare, Fastly, Akamai, DigitalOcean, Linode, OVH, Hetzner, Contabo, Vultr, Oracle, IBM Cloud and more.
Frequently asked questions
- What is an IP lookup?
- An IP lookup is a query that converts an IP address into the public metadata about it: its geographic location, the organization that owns the network (ASN + AS name), the hostname it points to (reverse DNS), and whether it appears on any spam blocklists. None of this is invasive — it's all data the address owners published themselves.
- Can I look up a domain name instead of an IP?
- Yes. The input box accepts an IPv4 / IPv6 address, a bare hostname (example.com, www.example.com), or a full URL (https://example.com/path?q=1). Domains and URLs are resolved via A / AAAA records first, and then the full intelligence pipeline runs against the resolved IP. If the domain has multiple A records, the first one returned by the resolver is used and the others are shown alongside it.
- What is reverse DNS (PTR record) and what does FCrDNS mean?
- Reverse DNS (PTR) is a DNS record that maps an IP back to a hostname — the opposite direction of a normal A/AAAA lookup. Forward-Confirmed reverse DNS (FCrDNS) means: when you take that PTR hostname and forward-resolve it, you get the original IP. Mismatched PTR is a major email-deliverability red flag — most spam filters reject mail from IPs whose PTR doesn't FCrDNS.
- What is an ASN?
- An Autonomous System Number is a globally unique identifier for a network on the Internet — usually owned by one ISP, cloud provider, university, or large enterprise. Every IP belongs to exactly one ASN at a given time. dnsverifier.com resolves ASNs via Team Cymru's free public DNS service (no API key, no rate-limit beyond DNS basics).
- How accurate is the geolocation?
- Country-level: ~99% accurate. City-level: ~70–80% for residential, near-perfect for corporate and cloud IPs. The data comes from ip-api.com which aggregates RIR allocations, BGP routing data, and ISP self-reports. Geolocation cannot tell you which physical house an IP is in — it only knows where the ISP routes that block.
- Why does my IP show 'hosting' or 'proxy'?
- ip-api.com flags an IP as 'hosting' when it belongs to a data center (AWS, GCP, Hetzner, OVH, etc.) rather than a residential ISP. 'proxy' means it's a known VPN, public proxy, or Tor exit. 'mobile' means it's part of a cellular carrier's network. These are flags for traffic categorization, not security verdicts.
- What's the difference between this and 'what is my IP'?
- A 'what is my IP' site shows you the public IP your browser is connecting from. dnsverifier.com's IP Lookup takes any IP you supply (yours or someone else's) and returns its public metadata. The two are complementary: get your IP from one site, paste it here for full intel.
- Can I look up private IPs like 192.168.1.1?
- Yes — the tool will classify the IP correctly (RFC 1918, loopback, link-local, CGNAT, etc.) and skip the network-bound lookups that wouldn't return useful data (geolocation, RIR WHOIS, DNSBL all assume a public address).
- Is the IP lookup free? Is there an API?
- Yes, completely free with no usage cap, no account, no API key. The page takes a `?h=…` query parameter (host or IP — for example `?h=example.com` or `?h=8.8.8.8`); the legacy `?ip=…` form still works. A formal API is not currently offered.