config change/modify best practices

[cliffordr2000]

               Hi Forum,

                    I anticipate getting a wide variety of answers to this question...and I am sure they will all be excellent. I am going to have to spend a great deal of time soon modifing configs on some Nex 5020's (4.1) we have. I do not have the luxury of the "checkpoint-rollback" function safety net. Aside from copying off the running config to an tftp server and bringing it back in when flames come out of the switch....what other ways are there to backout of a config error (fatfinger...wrong cli command...etc). I do like the "verify" function, but , unfortunately it will only warn me of typos and consistency (not if I meant to type "vlan add" not "add vlan") which we all know will cause havoc if not used correctly.. What I am looking for is a method(s) to get back to a stable state after a "ooops I meant vlan add not add vlan".

              Thank You All so Much,

                                                Ron Clifford

[LA-Engineer]

Do not save the running config to startup config unless you are sure everything is okay.  That is definitely an important one.

[Guru Mysoruu]

Hi Clifford,

Do the config,but don't save it.

Then you can use the command show archive config differences .

This command gives you the difference between startup config and running config.

A minus symbol (-) indicates that the configuration line exists in file1 but not in file2.

A plus symbol (+) indicates that the configuration line exists in file2 but not in file1.

Check the below link..

http://www.cisco.com/c/en/us/td/docs/ios/ios_xe/fundamentals/configuration/guide/2_xe/cf_xe_book/cf_config-diff_xe.pdf

Regards,

Guru

[milan.kulik]

Hi,

reload in 20

is my best friend any time I reconfigure Cisco devices on remote sites.

If you make a fatal CLI error and you lose your connection to the device, it reloads with the previous startup config without any need to call anybody on the site and to ask for a help.

You just need to issue

reload cancel

before the timer expires

(Or "reload in 20" again, if you are not finished yet. You just need to answer "No" to a prompt asking if to save the config changes made in that case.).

And as said here already: Don't save the config until you are sure it's OK!

Best regards,

Milan

[paul driver]

Hello

You can also negate using a shceduled reload and instead use the Cisco archive rollback feature

config
archive
path flash:backup
exit

sh archive
configure replace flash:backup-0  time 10
( if not verified within 10 minutes router will revert your changes back WITHOUT reloading your router)

Make some changes you to:

conf t
default inter fa0/0
default inter fa0/1

sh archive config differences

configure revert timer xxx ( if you wish to extend the timed rollback further)

configure confirm 

( ONLY  if you happy with your changes) - ##THIS JUST STOPS THE ROLLBACK IT DOES NOT SAVE THE RUNNING CONFIG## -If not applied, then the specified time limit  reached a rollback to the exisitng running config prior to changes will be initiated.

write mem

res

Paul