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IOS upgrade caused config commands to vanish

Recent upgrade on a 3640 to IOS 12.2.7c caused commands to vanish - "no ip directed broadcast" dissapeared from the running and startup config - it was still accepted as a command when typed in to the config. Reloading made no diference but it reappeared when the IOS was downgraded again. Is this command now a default that does not appear in the config or am I missing something - the router seemed to work okay either way. Thx in advance.


Re: IOS upgrade caused config commands to vanish

If it does not appear in the config it means that in that version of code it is a default value.


Re: IOS upgrade caused config commands to vanish

Your assumption is correct. "no ip directed broadcast" was changed to be the default setting in IOS 12.0. To minimize confusion for people upgrading from IOS 11.X and before, the reverse parser in 12.0 was jiggered to print the setting even though it was the default. (imagine the challenge of troubleshooting a failure because directed broadcast suddenly stopped working when the before and after configurations were identical :-)

Bottom line: Use care when upgrading--you really do need to read the release notes for the new IOS and every revision between where you started and where you are now. To the best of my knowledge, defaults have only changed between major releases, not within a release train. But the "show running everything" command has been on my (and many others') wish list for a long time...

Good luck and have fun!

Vincent C Jones

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