Admin Tip: Reverting back to start config without a reload
Posted by jrensink78 on January 31, 2009
I ran across an article quite a while back talking about being to move from the current running config to another configurations without a switch/router reload. This can definitely be a big time/bacon saver at work and in your lab. The command used is…
Router#configure replace (config location)
So if you wanted to revert back to the start config, you would enter “configure replace nvram:startup-config”. But you could also replace the running config with a config file on the bootflash or from a TFTP server. There are plenty of options.
If you are thinking that you could just do a “copy start run” command, that doesn’t quite do it. What that will do is add all of the start config commands to your running config. But it won’t remove any commands from the running config. So it’s like it melds the two together.
Personally, I like using this in my home lab. If any of you have 2600 series routers, you know how long they take to reboot. I saw one blogger joke that they take 2600 seconds to reload. It’s not quite that bad, but it feels that way some times. Using this command, you can forgo the reboot and get back to a clean config in not much time at all. Of course this won’t do the trick in every situation. Some things require a reboot in order to reset. But it can be a nice option in the toolbox.
Here is a link to the article if you’d like to take a look for yourself.
http://articles.techrepublic.com.com/5100-10878_11-6184709.html?tag=nl.e115
