scSubnetClassroom
Free tools for networking tutors

More teaching.
Less subnet marking.

Create individual IPv4 assignments, print worksheets and separate answer keys, and mark student answer files in your browser.

No signup, no student accounts and no paid subscription. Assignment creation and marking require JavaScript.

Read the worksheet guide ↗Preview a sample lesson

Free IPv4 lesson packs

Three assignments, printable worksheets, separate keys and a tutor guide. Available in English and Czech, with no account or email gate.

Download English packStáhnout českou sadu

Privacy & honest limits

Assignments, drafts and grading run in your browser. We do not receive your student codes or answer files. Assignment links contain the title and exercise settings in their URL fragment. Use a neutral title and student codes rather than real names.

Your browser stores your workspace and current draft on this device. Use “Clear local workspace” to remove them. Exported files remain wherever you saved them. Hosting providers may process ordinary access logs. Optional first-party usage analytics start only after you allow them. A random browser ID is kept for up to 30 days and a session ID for 30 minutes of inactivity. No student codes, answers, assignment titles, URLs with fragments or filenames are sent. Raw analytics is retained up to 90 days; privacy signals and your testing exclusion are respected. Change or withdraw your choice in Analytics preferences. Analytics is incomplete and does not identify individual people. No advertising scripts are added.

This is an open-book practice and formative assessment tool, not a secure exam system. Students can inspect the answer engine, alter files or use calculators. Imported files are not authenticated evidence of identity or work. Verify important results yourself.

The engine uses conventional IPv4 LAN rules for /8–/30; /31 and /32 are deliberately excluded. CSV scores are recomputed from answers on import. Free hosting has provider limits and no uptime guarantee.

All published tools and lesson packs are free. There is no checkout, paid service or donation request. Feedback is optional and is sent only when you choose to send an email from your own mail app.