TOOLOO · NETWORK TOOLS

Network maths without a network

Subnet calculation, IP address format conversion, and User-Agent parsing. All address and string arithmetic — no packets are sent.

Why DNS, WHOIS, and SSL checks are not here yet

DNS lookups, WHOIS, SSL certificate checks, HTTP header checks, site status and response time, port checks, ping, and traceroute all need a server to connect to a host on the user's behalf. Get that wrong and it becomes an internal network scanner anyone can direct: usable to probe localhost, private ranges, and cloud metadata endpoints, and bypassable through DNS rebinding. Doing it safely requires post-resolution address blocking, re-resolution and re-validation before every connection and after every redirect, a scheme allow-list, timeout and response size caps, per-IP rate limiting, and a non-root, network-isolated worker. Until all of that is built and verified, only the pure-computation tools are published.

Runs in your browser

These tools compute locally; your input never leaves this browser.

Subnet Calculator (CIDR)Work out the network address, broadcast, usable host range, and subnet divisions from an IP and prefix.IP Address Format ConverterConvert IPv4 between dotted decimal, integer, hexadecimal, and binary, and expand or compress IPv6.User-Agent ParserBreak down a User-Agent string into browser, engine, operating system, and device type.

Queried by our server

These tools need to contact the host, so the domain or URL you enter is sent to our server and queried by an isolated process.

What Is My IP AddressShows the public IP address this connection presents, and explains what it does and does not tell you.DNS LookupQuery a domain's A, AAAA, MX, TXT, NS, CNAME, SOA, and CAA records.DNS Propagation CheckerQuery the same record from several public resolvers at once to see how far a DNS change has spread.Reverse DNS Lookup (PTR)Find the host name an IP address maps back to — commonly needed for mail server setup.SSL Certificate CheckerConnect to a site, read its certificate, and show the subject, issuer, validity period, and days remaining.WHOIS LookupLook up a domain's registration details, registrar, creation and expiry dates, and name servers.HTTP Header CheckerFetch a URL's response headers to check caching, content type, and security settings.Website Status CheckerCheck whether a URL currently responds, showing the status code, response time, and any redirects.