This is a fairly easy question but if you’re a newbie in Cisco routers, then this can be a handy guide to tell you the details.

To see the version of IOS, there is one command which give a detailed overview of the software installed on the system (Cisco router or switch).Lets issue the command:

Certhacker#show version

The following sample information will be shown:

Show version will provide the following information:

• The version of the IOS
• Configuration register
• Hostname of the device
• The version of the ROM bootstrap
• The version of the boot loader
• The last way, time and date to power off the device
• Uptime of the device
• RAM
• Information about device hardware like Processor ID etc.
• Information about the interfaces installed on the device

It also show some additional information in case of a switch:

• The MAC addresses of all the interfaces on the switch
• Installed features like encryption etc.
• Time and date of configuration file modification

If you want to practice this command, you can use the router simulation in the following page:

Show Version Command Practice Simulation