|  | 4.2 | Router Show Commands
| 4.2.4 | Lab: router show commands
| Lab Activity
| This lab will help you become familiar with the router show commands. The show commands are the most important information gathering commands available for the router. The show running-config (or "show run") is probably the single most valuable command to help determine the current status of a router because it displays the active configuration file running in RAM. The show startup-config (or "show start") command displays the backup configuration file that is stored in non-volatile or NVRAM. This is the file that will be used to configure the router when it is first started or rebooted with the "reload" command. All of the detailed router interface settings are contained in this file. The show flash command is used to view the available and the amount used of flash memory. Flash is where the Cisco Internetwork Operating System (IOS) file or image is stored. The show arp command displays the router's IP to MAC to Interface address mapping. The show interface command displays statistics for all interfaces configured on the router. Show protocol command displays global and interface-specific status of configured layer 3 protocols (IP, IPX etc.).