Category: CCNA Study Guide

Command Undebug All Use This command stops all debugging on the router. Syntax Router#undebug all Example Since there is many different debugging options, we have added a debugging section with some of the more useful debugs for a CCNA candidate. R2#debug ip packet IP packet debugging is on …

Command Write Terminal Use Shows the current configuration of a device. This is deprecated (obsolete) command, but is less typing then using the show run command. This is one of the first commands you will enter when trying to understand how a device is configured. Syntax Router#write terminal …

Command Reload Use This command is used to reboot the Cisco device. Syntax Router# reload Options -noverify Don’t verify file signature before reload -verify Verify file signature before reload -LINE Reason for reload -at Reload at a specific time/date -cancel Cancel pending reload -in Reload after a time …

Command Clear Use This command is used to clear various counters in IOS as well as to reset various routing protocol adjacencies. Syntax Router#clear <option> Optional Switches aaa Clear AAA values access-list Clear access list statistical information access-template Access-template adjacency Adjacent nodes alps Clear Alps appletalk Reset AppleTalk …

Command Clock Set Use Sets the date and time on the router. It is important to configure your date and time in order to properly manage logs. Syntax Router# clock set hh:mm:ss DAY MONTH YEAR OR Router# clock set hh:mm:ss MONTH DAY YEAR Example In the below example …

Command Write Use This is deprecated (obsolete) command. It saves the current running configuration. Most experienced network proffessionals use this command because you can simply type “wr” to save your running config instead of using the lengthier copy running-config startup-config command. Syntax Router>write Example In this example the …

Command Erase Startup-config Use This command lets you erase your startup-configuration. When you reload the router or switch it will return to its default configuration. Syntax R1#erase startup-config R1#reload Example In the below example R1’s startup configuration is erased. R1#erase startup-config Erasing the nvram filesystem will remove all …

Command Copy Running-config Startup-config Use This command lets you save your running configuration to the router’s startup configuration (NVRAM) so it will survive a reload. Syntax Router#copy running-config startup-config Example In the below example R1’s startup configuration is saved. R1#copy run start Destination filename ? Building configuration… R1#

Command Setup Use This command provides a simple wizard that helps you setup your router with a simple configuration. If you find yourself accidentally in setup mode (by pressing ‘yes’ when the router boots then hold down the control and c keys to exit. Syntax R1#setup Example In …

Command Debug Use This is a very useful but sometimes dangerous command. It allows you to see how the router or switch processes many different protocols. If your not careful you can lock yourself out of the device, or even lockup the router/switch so no further traffic will …