New IOS image, config changes (missing lines)

Answered Question
Apr 23rd, 2007
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Hello All, I have recently upgraded a 2811 router from IOS version : c2800nm-ipbase-mz.124-3c

to the new version : c2800nm-advipservicesk9-mz.124-11.T1


After upgrade certain config entries are no longer in the router.

The "resource policy" entry is no longer there. As well as the "ip subnet zero" and "ip classless" commands are missing.


Are these features enabled by default in the new version of IOS, or am I missing something?


Any help would be greately appreciated.


Thank you.

Dmitry.

Correct Answer by ankbhasi about 10 years 2 months ago

Hi Dmitry,


As updated by Rick , mostly in all latest releases these commands are enabled by default so they are not displayed till you go in reverse i.e if you disable any of this command like "no ip subnet zero" or "no ip classless" and then sh run and you will find these available in sh run command.


Because it is enabled by default in many latest releases they are not displayed in "sh run" output.


HTH


Ankur

Correct Answer by Richard Burts about 10 years 2 months ago

Dmitry


While these lines no longer show up when you do show running-config (or show startup-config) I do not believe that any of these underlying behaviors have changed.


Cisco has had the approach that in general default values do not show up in the config. There have been certain exceptions where default values do show up, especially for commands where the default behavior changed (as it did for ip classless and ip subnet-zero). I assume that someone at Cisco decided that the behaviors were enough well known that they no longer need to show up in the config.


HTH


Rick

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Correct Answer
Richard Burts Mon, 04/23/2007 - 08:54
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Dmitry


While these lines no longer show up when you do show running-config (or show startup-config) I do not believe that any of these underlying behaviors have changed.


Cisco has had the approach that in general default values do not show up in the config. There have been certain exceptions where default values do show up, especially for commands where the default behavior changed (as it did for ip classless and ip subnet-zero). I assume that someone at Cisco decided that the behaviors were enough well known that they no longer need to show up in the config.


HTH


Rick

Correct Answer
ankbhasi Mon, 04/23/2007 - 09:00
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Hi Dmitry,


As updated by Rick , mostly in all latest releases these commands are enabled by default so they are not displayed till you go in reverse i.e if you disable any of this command like "no ip subnet zero" or "no ip classless" and then sh run and you will find these available in sh run command.


Because it is enabled by default in many latest releases they are not displayed in "sh run" output.


HTH


Ankur

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