Cisco WS-X4424 Hardware Maintenance Manual - Page 118

Changing Configuration Register Settings

Get Cisco WS-X4424 - Catalyst 4000 Series 10/100/1000 BASE-T Copper Gigabit Ethernet Module PDF manuals and user guides
UPC - 746320543758
View all Cisco WS-X4424 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 118 highlights

Virtual Configuration Register Settings Changing Configuration Register Settings Some common reasons to modify the value of the virtual configuration register follow: • Recover a lost password. • Change the console baud rate. • Enable or disable the Break function. • Manually boot the operating system using the b command at the ROM monitor prompt. • Force the router to boot automatically its system image in Flash memory, or boot as per any boot system commands that are stored in its configuration file in NVRAM. Note If the router finds no boot system commands, it uses the configuration register value to form a filename from which to boot a default system image stored on a network server. (See Table B-3.) To change the configuration register while running the IOS software, follow these steps: Step 1 Enter the enable command and your password to enter the privileged level, as follows: router> enable Password: router# Step 2 At the privileged-level system prompt (router #), enter the command configure terminal. You will be prompted as shown in the following example: router# configure term Enter configuration commands, one per line. Edit with DELETE, CTRL/W, and CTRL/U; end with CTRL/Z Step 3 To set the contents of the configuration register, enter the config-register value configuration command where value is a hexadecimal number preceded by 0x (see Table B-3), as in the following: config-register 0xvalue (The virtual configuration register is stored in nonvolatile memory.) Step 4 Exit the configuration mode by entering Ctrl-Z. The new value settings will be saved to memory; however, the new settings do not take effect until the system software is reloaded by rebooting the router. Step 5 To display the configuration register value currently in effect and the value that will be used at the next reload, enter the show version EXEC command, and the value will be displayed on the last line of the screen display as in the following example: Configuration register is 0x142 (will be 0x102 at next reload) Step 6 Reboot the router. The new value takes effect. Configuration register changes take effect only when the server restarts, for example, when you switch the power off and on or when you issue a reload command from the console. B-2 Cisco 4000 Series Hardware Installation and Maintenance

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
B-2
Cisco 4000 Series Hardware Installation and Maintenance
Virtual Configuration Register Settings
Changing Configuration Register Settings
Some common reasons to modify the value of the virtual configuration register follow:
•
Recover a lost password.
•
Change the console baud rate.
•
Enable or disable the Break function.
•
Manually boot the operating system using the
b
command at the ROM monitor prompt.
•
Force the router to boot automatically its system image in Flash memory, or boot as per any
boot system
commands that are stored in its configuration file in NVRAM.
Note
If the router finds no
boot system
commands, it uses the configuration register value to form
a filename from which to boot a default system image stored on a network server. (See Table B-3.)
To change the configuration register while running the IOS software, follow these steps:
Step 1
Enter the
enable
command and your password to enter the privileged level, as follows:
router>
enable
P
assword:
router#
Step 2
At the privileged-level system prompt (router #), enter the command
configure terminal.
You will be prompted as shown in the following example:
router#
configure term
Enter configuration commands, one per line.
Edit with DELETE, CTRL/W, and CTRL/U; end with CTRL/Z
Step 3
To set the contents of the configuration register, enter the
config-register
value
configuration command where
value
is a hexadecimal number preceded by 0x
(see Table B-3), as in the following:
config-register 0x
value
(The virtual configuration register is stored in nonvolatile memory.)
Step 4
Exit the configuration mode by entering Ctrl-Z. The new value settings will be saved to
memory; however, the new settings do not take effect until the system software is reloaded
by rebooting the router.
Step 5
To display the configuration register value currently in effect and the value that will be used
at the next reload, enter the
show version
EXEC command, and the value will be displayed
on the last line of the screen display as in the following example:
Configuration register is 0x142 (will be 0x102 at next reload)
Step 6
Reboot the router. The new value takes effect. Configuration register changes take effect
only when the server restarts, for example, when you switch the power off and on or when
you issue a
reload
command from the console.