CCNA Cisco Certified Network Associate Study Guide - FTP Server

Managing Configuration Registers 331
Remember that in hex, the scheme is 0–9 and A–F (A=10, B=11, C=12, D=13,
E=14, and F=15). This means that a 210F setting for the configuration register
is actually 210(15), or 1111 in binary.
Checking the Current Configuration Register Value
You can see the current value of the configuration register by using the show
version command (sh version or show ver for short), as in the following
example:
Router#sh version
Cisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-I-M), Version 12.0(3)T3,
RELEASE SOFTWARE (fc1)
[output cut]
Configuration register is 0x2102
The last information given from this command is the value of the configuration
register. In this example, the value is 0x2102, which is the default
setting. Notice the show version command provides the IOS version. In the
example above, it shows the IOS version as 12 0(3)T3.
Changing the Configuration Register
You can change the configuration register value to modify how the router
boots and runs, as follows:
� Force the system into the ROM monitor mode
� Select a boot source and default boot filename
� Enable or disable the Break function
� Control broadcast addresses
� Set the console terminal baud rate
� Load operating software from ROM
� Enable booting from a TFTP (Trivial File Transfer Protocol) server