Network utilities
Each one runs entirely in your browser — nothing you type leaves your device. No accounts, no tracking beyond standard analytics.
IP Lookup & Geolocation
Look up any IP. City, region, ISP, ASN, timezone, map. Works for IPv4 and IPv6.
Open →Subnet Calculator
CIDR ↔ mask ↔ host count. Network and broadcast addresses, usable host range.
Open →IP Converter
Decimal ↔ binary ↔ hex. See exactly what's in those four octets.
Open →CIDR Range Tool
Expand a CIDR block to start/end IPs, or aggregate a list of ranges.
Open →MTU / MSS Calculator
Find your path MTU and the matching TCP MSS. Includes overhead for VPN tunnels.
Open →Bandwidth & Transfer
How long will 500 GB take on a 100 Mbps link? Convert between bps, Bps, and GB/hr.
Open →Password Entropy
Estimate how long a password resists offline cracking. Better than dictionary advice.
Open →Look-up tables
Quick-reference pages for the things you Google constantly.
Private IP Ranges
RFC 1918 + CGNAT + link-local + loopback. The cheat sheet you keep half-remembering.
Open →Default Router IPs
Linksys, Netgear, ASUS, TP-Link, Ubiquiti — what's the default gateway and login?
Open →Port Reference
What runs on port 5060? On 8443? The ports cheat sheet for sysadmins and gamers.
Open →DNS Record Types
A, AAAA, MX, TXT, CNAME, NS, SOA, SRV, CAA — what they do and when you'd use them.
Open →Why Tank?
Most "what's my IP" sites are sad. Stuffed with autoplay video, popup ads, fake "your computer is infected" warnings, and a stripe at the top that says BUY OUR VPN. We thought: that's a lot of work to dress up a number.
Tank shows you the number. Tank is a real cat in northern Vermont. He's a tabby with strong opinions and zero patience for nonsense. We think he's the best mascot in the IP-lookup business, and we're not going to argue with you about it.
Beyond the front door, this is a serious tool site for sysadmins, network engineers, gamers configuring port forwards, and home users trying to figure out why their router won't talk to their printer. Everything runs in your browser. Nothing you type or paste is sent to us. The only thing we ever know about you is what your browser sends to Cloudflare's edge — same as visiting any other site on the internet.