Other Free Sources

Subnetting

• subnetting.org
  • A great resource to practice subnetting with a wide range of random
• SolarWinds network calculator
  • A nice subnetting calculator that shows

Cisco IOS Commands

Here are two excellent collections of Cisco IOS command cheat-sheets and reference guides.
GitHub - r7perezyera/Cisco-IOS-Command-CheatSheets: A collection of Cisco switch and router IOS commands that everyone can use as reference/guide.

GitHub - HerrSpace/CCNA-Cheat-Sheet: A comprehensive CCNA CLI reference.