IP Lens | Fusing Bits

IP addresses

Showing: your own IP addresses

URL info

Look up a domain, URL, or an IP with a reverse-DNS record to see its associated URL info here.

IPv4 / IPv6 details

	IPv4	IPv6

Notes

IP data is sourced from public geo-IP providers: ipify (address detection), ipapi.co, ipwho.is, freeipapi.com, ipinfo.io, and geojs.io (geo/ISP details, tried in that priority order).
Blacklist status uses the Spamhaus ZEN DNSBL, which only covers IPv4 — the IPv6 column always shows "N/A" for this check, not because we couldn't find it, but because that blacklist doesn't apply to IPv6 at all.

Look up a domain or URL in the search bar above to see its WHOIS and DNS records (A, AAAA, MX, TXT, NS) here.

Notes

Domain and URL lookups use DNS-over-HTTPS (Google) for DNS records and a small community WHOIS service for registrar/creation date only — the WHOIS data may be incomplete or occasionally unavailable.
Looking up an IP address also attempts a reverse DNS (PTR) lookup to find an associated hostname — many IPs (especially residential/dynamic ones) simply have no PTR record, which is normal and shows as "Unknown", not an error. On shared hosting, the PTR record usually points to the host's own infrastructure, not to your specific domain — that's normal too, not a bug.
Certificate history comes from crt.sh (Certificate Transparency), a free public service — it can be slow or occasionally unavailable.
DKIM detection tries a handful of common selectors automatically (google, selector1, selector2, default, k1, dkim, s1, mail) — its DNS record name always includes a "selector" chosen by whoever set up the mail server, so if the real one isn't in that list, DKIM will show as not found even though a record may genuinely exist.

This tab always reflects your own browser — it can't be checked for a looked-up domain or IP.

Security & permissions context

This site's security headers

About fusingbits.com itself (the page hosting this tool) — not about you or a looked-up domain. Browsers block reading another site's security headers cross-origin, so this can never work for a lookup target, only for this site's own page.

Notes

This page sets a Content-Security-Policy via an HTML <meta> tag, restricting which domains it can contact — but a meta-tag CSP doesn't appear as an actual HTTP response header, so "This site's security headers" above will still show "Not set" for it. Setting it as a real HTTP header (at the hosting level) would additionally allow directives like frame-ancestors, which meta tags can't enforce at all.

This tab always reflects your own browser — it can't be checked for a looked-up domain or IP.

WebRTC local candidates

Notes

WebRTC can leak your local (and sometimes real public) IP address even behind a VPN or proxy: to set up a peer connection, browsers gather "ICE candidates" that can include your actual network addresses — a well-known privacy quirk, not a bug in this tool. It's why some VPNs specifically advertise "WebRTC leak protection".
Client MAC address is not accessible from a normal web browser.
A native helper app or local agent is required for MAC diagnostics.

This tab always reflects your own browser — it can't be checked for a looked-up domain or IP.

Browser & device

User-Agent analyzer

Paste any User-Agent string to parse it — defaults to your own. Or try a preset:

HTTP headers sent by your browser

Via a public echo service — shows what a server actually receives from you.

Network API context

Latency check

Approximate — measured via HTTPS requests, not a real ICMP ping, so it's higher than a true ping to the same host.

Speed test

Download speed only — a static site has no server-side endpoint to receive an upload against, so upload speed can't be measured this way. Downloads real test files from this site (up to 100 MB) to measure your connection, starting small and escalating only if needed. Opt-in — nothing downloads until you click.

Timezone check

A mismatch between your browser's timezone and your IP's timezone is a classic VPN/proxy indicator.

Precise location check

Opt-in only — nothing is requested until you click. Compares your device's actual GPS/network location (via a browser permission prompt) against your IP-based location above.

IP history (this session)

Notes

The HTTP headers view uses a public echo service (httpbin.org, with a fallback) that can occasionally be slow or unavailable.

Subnet / CIDR calculator

Standalone tool — IPv4 only, works offline, not tied to your IP or any lookup.

IP address format converter

IPv4 only — paste a dotted decimal, integer, hex, or binary address.

IPv6 expand / compress

Paste any IPv6 address (compressed or full) to see both forms.

IPv6 EUI-64 / SLAAC calculator

From a MAC address, computes the IPv6 interface identifier a device would generate for itself automatically.

URL parser

Breaks a URL down into its parts — doesn't fetch it, just parses the text.

URL encode / decode any text:

Unix timestamp converter

Accepts seconds or milliseconds — detected automatically from digit count.

IP range → CIDR blocks

Enter a start and end IPv4 address to get the smallest set of CIDR blocks covering that range exactly.

CIDR overlap checker

Enter two IPv4 CIDR blocks to check whether they conflict.

Base64 encode / decode

UTF-8 safe — handles accented and non-Latin characters correctly.

MTU / fragment size calculator

Max payload that fits in one packet for a given MTU and header overhead. Common presets: Ethernet 1500, PPPoE 1492, jumbo frames 9000.

IP list → CIDR aggregator

Paste a list of IPv4 addresses (one per line, or comma/space separated) — duplicates are removed and contiguous runs are merged into CIDR blocks. Generalizes the range converter above to any list, gaps included.

Email header analyzer

Paste raw email headers (including the "Received:" lines) to trace the chain of mail servers it passed through, with a geo-lookup of each IP found. Runs entirely against what you paste — nothing is sent anywhere except the IP geo-lookups.

DNS propagation checker

Queries the same domain on two different public resolvers (Google and Cloudflare) — a mismatch usually means a recent DNS change is still propagating.

Reverse ASN lookup

Which IP prefixes a given Autonomous System announces — via RIPEstat, RIPE NCC's public data service (covers global BGP data, not just the RIPE region).

VLSM subnet splitter

How many bits to borrow to get at least N equal subnets from a base network.

JWT decoder

Decodes header and payload only — never verifies the signature. Nothing is sent anywhere, all decoding happens locally.

IP address classifier

Private, loopback, link-local, multicast, or public — based on well-known reserved ranges (IPv4 and IPv6).

Random IP/MAC generator

For demo/testing purposes — generates a random private IPv4 and a random MAC address.

Well-known ports reference

Search by port number or service name. Not exhaustive — covers the ports you're most likely to run into.

HTTP status code reference

Search by code or keyword. Covers the most common codes, not the full IANA registry.

HTTP methods reference

Search by method name or keyword.

Subnet mask / wildcard mask / CIDR reference

Search by prefix (e.g. 24), or by a mask/wildcard value — useful for Cisco-style ACL configs that use wildcard masks instead of CIDR.

Network glossary

Plain-language explanations of the jargon this tool shows elsewhere.