toolsforwebNetwork
Subnetting, IP addressing, and DNS helpers: subnet and IPv6 prefix calculators, IP base conversion, DNS lookups, and User-Agent parsing.
About Network
Helpers for addressing and troubleshooting networks. The IPv4 subnet calculator turns any CIDR or netmask into the network and broadcast address, usable host range, host count and wildcard mask; the IPv6 calculator does the same for prefixes with exact 128-bit arithmetic. Convert an IPv4 address between dotted-decimal, integer, hex and binary.
To look outward, see the public IP address your connection presents, look up A, AAAA, MX, TXT, NS and CNAME records for a domain, and break down a User-Agent string into browser, OS, device and bot details. DNS lookup and What Is My IP use our server; the calculators and parser run in your browser.
Questions
How many usable hosts are in a /24?
254. A /24 has 256 addresses, minus the network and broadcast addresses. A /31 is the exception: point-to-point links use both addresses, which the subnet calculator handles.
Why does What Is My IP show a different address than my computer?
Your computer usually has a private address on your local network; the router translates it to one public address for the internet. A VPN or proxy replaces that public address with its own.
Why are my DNS changes not showing yet?
Resolvers cache records for their TTL, so old answers can linger until it expires. The DNS lookup asks our server's resolver rather than your own, which helps you check whether a change is visible from outside your network.