A wiki page dedicated to explaining Troubleshooting Commands for IOS Devices in practical terms. The intent is to compile commands relevant to troubleshooting the behavior of a Cisco IOS device itself (CPU, memory, performance, etc.) and to provide an accompanying description of each.
As the network engineer for your company you are responsible for all network-related tasks. One day your security officer comes to you and asks is you can further enhance the network security. He wants you to implement an IOS Firewall feature to protect incoming traffic