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Understanding the network.pdf - Back to Home

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outer and enter <strong>the</strong> break sequence when <strong>the</strong> router begins <strong>the</strong> boot<br />

process after <strong>the</strong> "bootstrap" banner has been displayed:<br />

System Bootstrap, Version 11.0(10c), SOFTWARE<br />

Copyright © 1986-1996 by Cisco Systems<br />

2500 processor with 14336 Kbytes of main memory<br />

Abort at 0x1098FEC (PC)<br />

><br />

NOTE<br />

Keep in mind that whenever you make a conf-reg change, it will need<br />

<strong>to</strong> be set back <strong>to</strong> "running" conf-reg setting after you have corrected<br />

<strong>the</strong> problem. This can be done using <strong>the</strong> <br />

command in global configuration mode. You can, by <strong>the</strong> way, avoid<br />

al<strong>to</strong>ge<strong>the</strong>r, and change <strong>the</strong> conf-reg setting in global<br />

configuration mode if you have access.<br />

Disaster recovery on Cisco routers using rommon and conf-reg<br />

settings is straight- forward because all Cisco routers use <strong>the</strong> same<br />

basic boot sequence:<br />

1. The router is powered up.<br />

2. It checks its conf-reg settings.<br />

3. It checks <strong>the</strong> NVRAM for boot loader information.<br />

4. It loads <strong>the</strong> IOS.<br />

5. It loads <strong>the</strong> NVRAM config.<br />

Because <strong>the</strong> conf-reg is <strong>the</strong> first boot element checked, it is possible<br />

<strong>to</strong> configure <strong>the</strong> router <strong>to</strong> do a number of different things just by<br />

changing its conf-reg settings. If possible, before making any

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