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Chapter 7
Managing a Cisco Internetwork
Cisco 2500 Series Commands
To change the configuration register on a 2500 series router, type o after cre-
ating a break sequence on the router. This brings up a menu of configuration
register option settings. To change the configuration register, enter the com-
mand o/r, followed by the new register value. Here is an example of turning
on bit 6 on a 2501 router:
System Bootstrap, Version 11.0(10c), SOFTWARE
Copyright (c) 1986-1996 by cisco Systems
2500 processor with 14336 Kbytes of main memory
Abort at 0x1098FEC (PC)
>o
Configuration register = 0x2102 at last boot
Bit# Configuration register option settings:
15 Diagnostic mode disabled
14 IP broadcasts do not have network numbers
13 Boot default ROM software if network boot fails
12-11 Console speed is 9600 baud
10 IP broadcasts with ones
08 Break disabled
07 OEM disabled
06 Ignore configuration disabled
03-00 Boot file is cisco2-2500 (or 'boot system' command)
>o/r 0x2142
Notice the last entry in the router output is 03-00, which tells the router what
the IOS boot file is. By default, the router will use the first file found in the flash
memory. If you want to boot a different file name you can either change the
configuration register or use the boot system ios_name command. You can
also load an IOS image from a TFTP host by using the command boot system
tftp
ios_name ip_address.
Reloading the Router and Entering Privileged Mode
At this point, you need to reset the router, as follows:
From the 2600 series router, type reset.
From the 2500 series router, type I (for initialize).
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