Author: Tobias - Page 7 - NetGuide

VLSM Subnet Calculator

Split a network into variable-size subnets via VLSM – by host demand, with network, mask, range and broadcast. Runs in the browser.

Generate a Wake-on-LAN magic packet – hex bytes plus ready-made commands for Linux and PowerShell. Runs entirely in the browser.

Translate a cron expression into plain English – live. Shows exactly when a cron job runs. Runs in the browser.

Calculate MSS from MTU – including IPv4/IPv6 headers and tunnel overhead (PPPoE, WireGuard, IPsec, GRE, VXLAN). Runs in the browser.

Test regular expressions online – with flags, a live match list and groups. Uses the JavaScript regex engine, runs in the browser.

Check colour contrast per WCAG – contrast ratio plus AA and AAA pass for normal and large text, with a live preview.

Generate an Nginx server block for a reverse proxy – with backend, optional SSL (Let’s Encrypt) and WebSocket support.

Generate systemd unit files – a service and an optional timer, with ExecStart, User, Type and restart policy. Runs entirely in the browser.

Generate QR codes from a URL or text – with adjustable size and error correction, downloadable as PNG. Runs in the browser.

Calculate password strength as entropy in bits – including character space and estimated time to crack. Runs locally in the browser.

Generate version 4 (random) UUIDs – single or as a list. Cryptographically secure random values, entirely in the browser.

Validate, format and minify JSON online – with error display. Runs entirely in the browser, no data is sent.