24 - 238 CCNA 2: Routers and Routing Basics v3.1 Instructor Guide – Module 2 Copyright © 2004, Cisco Systems, Inc.
The syntax of IOS commands can be complex. The feature used to recall commands can help
students save time when they program or troubleshoot a router.
2.2.9 Troubleshooting command line errors This troubleshooting lab allows students to log into the router and access various modes.
Demonstrate the use of the question mark (?) as a helpful tool for students who do not know
which command to enter.
Also demonstrate the use of the history command as a helpful tool for students to
troubleshoot problems without retyping repeated commands.
2.2.10 The show version command The show version command displays information about the Cisco IOS software version.
This information includes the system image file name and the location from which it was
booted. It also contains the configuration register and the boot-field setting. Explain that an
important aspect of router and IOS maintenance is to know exactly which version of the IOS is
being used.
Cisco has numerous major and minor IOS releases. There are many different versions and
different features to meet the requirements of a network. Students should know that the show
version command shows much more than just the version of the IOS. This is an important
command. Explain to students is that this is the only command that can be used to examine
the configuration register.