IP Address Subnetting Tutorial - A technical introduction to IP addressing and address subnetting in an easy-to-understand tutorial format. Daryl's TCP/IP Primer - LAN Administrator's Guide to TCP/IP and routing for Internet-connected LANs. IP Addresses - A Cisco document explaining what IP addresses are. [HTML/PDF] Online IP Subnet Calculator - Online IP subnet, CIDR/VLSM/supernet and wildcard mask calculators. Network Calculators - A subnet mask and network/node calculator including IP address and mask conversion. Wikipedia: Subnetwork - A detailed article about subnetting from the free encyclopedia. SubnetOnline.com - Online IP subnet calculators, subnetting tutorials and online network tools for IPv4 and IPv6. Subnetting Secrets - Teaches IT students and networking professionals how IP addressing works. Lessons include easy subnetting, subnet mask calculation, binary math and VLSM. IP subnetting exerciser - This site automatically generates and reviews an endless list of exercises on IP subnetting, starting from different presets. DrizWork - Provides a complete listing of all routable IPv4 IP addresses, geolocation information as well as registration information. SubnettingPractice.com - Subnetting practice site. Practice and calculaters for IPv4, IPv6, VLSM, CIDR, Binary, Hex. IP Chalk - IP exercises to practise all kinds of IP notations, calculations and subnetting challenges. Subnet Calculator Ninja - Powerful IP subnet calculator that supports IPv4 and IPv6 addresses. Includes detailed explanation about the different IP types