Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Overwrite Running-config

Is there a way to overwrite the running config with a new config. I have a new config in text which I want to use for a router which already has a bunch of crap on it. I cant tftp into it so I need another way of doing this. I tried copy pasting the new config but it just appends it of doesnt overwrite. Help please

Hall of Fame Super Silver

Re: Overwrite Running-config


What I have done when I wanted a complete replacement of the running config was to tftp the new config to the router into startup config (which does do a complete replacement) and then to reboot the router which will load the new config cleanly in place of the old config. But if you are not able to tftp to the router then this will not work for you.

I am not aware of any other option for a clear replacement of running config.



New Member

Re: Overwrite Running-config

I tried doing tftp but somehow even though I gave an IP to the routers E0 int and then connected to the router through that interface, and made sure they're both in the same subnet..they dont see each other..I cant ping from one to another!!! so cant tftp!!

New Member

Re: Overwrite Running-config

Hi, the running config is changed when you add to or rewrite the config, when you save your changes they are copied into the start-up config. If the router is in production making changes to the config should be done with caution. What do you need to change? the interface config? the routing protocol? vlan assignment?. I usually will copy the selected change and past it onto the device, you need to be in config mode or interface mode depending on the change. Once you do wrote memory the current running config is ssaved as the startup config. let me know what you are changing I amybe able to help more, check out the link below.

New Member

Re: Overwrite Running-config

The router is offline. The plan is to load a new config onto it and put it back on the network so it acts as a gateway between the production network and the LAB Network that we have setup here. So, this router has a bunch of snmp traps..dhcp logging etc that I want to get rid off. It would take me a long time to remove each one and then copy the new config....there has to be a better way!!


Re: Overwrite Running-config

How about copying ALL files in nvram to flash (for backup purposes), if they exist in nvram, and doing a 'write erase' or 'erase nvram:'

Reboot your router then paste the new config and write it to nvram.

(of course, requires an outage of the routers services duing the reboot)

Or you can copy the new config to nvram (or flash for that matter) called 'new-config' for example; then use the 'boot config' command to specify the device and filename of the configuration file the router will use to initialize with...then reboot the router.

(this will save your startup-config and let you use the new config....test then delete the config you want when all testing successful)