IPv4 Subnet / CIDR Cheat Sheet
One A4 page: every IPv4 prefix, mask, wildcard, address count, subnet boundaries and special-range reminders.
A4 desk and field references for subnetting, IPv6, ports, DNS, packet sizes, Wi-Fi and cellular bands.
Each reference has a dedicated one-page A4 layout. Use Print / Save PDF at 100% scale with browser headers and footers disabled. Sources and longer explanations remain on the web page.
10 tools and references
One A4 page: every IPv4 prefix, mask, wildcard, address count, subnet boundaries and special-range reminders.
Work through original subnetting examples for boundaries, host capacity and address allocation.
Recognize common private, shared, loopback, documentation and local address ranges.
A curated, printable guide to common service ports and transport choices.
Understand common DNS record types, TTLs and frequent configuration mistakes.
A one-page A4 reference for IPv6 notation, prefix sizes, address types, multicast and reverse DNS.
A one-page A4 reference for frame size, VLAN overhead, IP MTU, TCP MSS and tunnel budgeting.
One A4 page explaining Wi-Fi generations, channel widths, spatial streams and PHY rates without promising Internet speeds.
One A4 page of current /interface/wifi band selectors, package distinctions and channel-width syntax.
One A4 field reference for selected European-relevant LTE and NR bands, duplex modes, frequency ranges and RouterOS selectors.