Flash Card Boot on 2811

Answered Question
Dec 18th, 2009

We have a 2911 router with an embedded switch that has the IOS on a Compact Flash Card.  After configuring the router and the switch module, I save the running-config to the Flash Card.I do not write the config to NVRAM because when I turn off the router I want the configuration to be purged, due to security regulations.  So everyday I insert the Compact flash card and boot the router.  I connect a laptop via hyperterminal and then copy the config from the flash card to the startup-config and reload the router.  This works, however is there a way that the router can boot from the configuration file on the Flash and it won't save the configuration into NVRAM?  In other words, I would like to merely plug the Flash Card in and turn on the router and the configuration file is loaded.

Correct Answer by Jon Marshall about 7 years 2 months ago

gdwingnuts wrote:


Your answer was very helpful, thankyou!  Another question.  If I remove the Flash Card and attempt to boot the router without it, with the boot config command in place, will it boot to its original startup-config or hang at the >rommon prompt?


Sorry, haven't used it in a while so not 100% sure but from memory it does not default to NVRAM so if you specify a location such as flash and it can't find it then it won't boot which sounds like what you want. Worth testing though.


Jon

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Jon Marshall Fri, 12/18/2009 - 09:22

gdwingnuts wrote:


We have a 2911 router with an embedded switch that has the IOS on a Compact Flash Card.  After configuring the router and the switch module, I save the running-config to the Flash Card.I do not write the config to NVRAM because when I turn off the router I want the configuration to be purged, due to security regulations.  So everyday I insert the Compact flash card and boot the router.  I connect a laptop via hyperterminal and then copy the config from the flash card to the startup-config and reload the router.  This works, however is there a way that the router can boot from the configuration file on the Flash and it won't save the configuration into NVRAM?  In other words, I would like to merely plug the Flash Card in and turn on the router and the configuration file is loaded.


Have you tried the boot config command -


http://www.cisco.com/en/US/docs/ios/12_3/configfun/command/reference/cfr_1g01.html#wp1030573


Jon

gdwingnuts Fri, 12/18/2009 - 09:47

Your answer was very helpful, thankyou!  Another question.  If I remove the Flash Card and attempt to boot the router without it, with the boot config command in place, will it boot to its original startup-config or hang at the >rommon prompt?

Correct Answer
Jon Marshall Fri, 12/18/2009 - 10:10

gdwingnuts wrote:


Your answer was very helpful, thankyou!  Another question.  If I remove the Flash Card and attempt to boot the router without it, with the boot config command in place, will it boot to its original startup-config or hang at the >rommon prompt?


Sorry, haven't used it in a while so not 100% sure but from memory it does not default to NVRAM so if you specify a location such as flash and it can't find it then it won't boot which sounds like what you want. Worth testing though.


Jon

Leo Laohoo Fri, 12/18/2009 - 20:31

If you boot the router without a CF/USB the router will go into ROMmon.

gdwingnuts Mon, 12/21/2009 - 14:18

Don't want to beat a dead horse but...  If I were to set the boot config command on my 2811 to boot to slot0: Then on one flash card have my configuration and on another flash card have the same IOS but with a different config will the router boot to which ever config (i.e., flash card) I insert? I have to remove one config and install another due to security issues each day. I'm trying to simplify this process.

Leo Laohoo Mon, 12/21/2009 - 15:28

If I were to set the boot config command on my 2811 to boot to slot0:
Won't work because the 2811 doesn't "recognize" slot0.


Here's an option:  IOS in a CF but your config file in USB or boot IOS from the USBslot1: and config file in CF or USBslot2:   This is possible.

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