My local PC has an IP address of 192.168.56.252
and I’m running some free software called TFTP 32
so on the router lets first see
if I can ping the TFTP server, which I can
It's important to check that you’ve got connectivity
so now I'll type copy running-config ?
and I have the option TFTP, so I'm gonna say tftp
the IP address of the TFTP server is 192.168.56.252
I'll accept the default file name of r1-config or config
as you can see the file is being copied to the TFTP server
and I can see that in the output on the router as well.
So many bytes have been copied in so many seconds.
In windows I'll open the file with word pad and as you can see here
I have a configuration of my router. So let’s make a change.
I'll set the line vty from 0 to 20 (line vty 0 20)
specify login and specify a password of cisco
that is different to this current config on the TFTP server
I’ll copy the config to the TFTP server again.
I’ll specify the same filename and let's open up the file
and as you can see now, the changes have been made.
So the file was successfully copied to the TFTP server.
It's good practice once again to copy a config
I could also copy the start up config to the TFTP server.
Specify the IP address and let’s view the actual copy taking place.
I’ll call this r1-start-config
and that file has been copied to the TFTP server,
we can also see that on the router and in windows.
I can see the startup config.
Now what’s important to note is
the startup config is different to the running config,
so notice the VTY lines are different on startup and running config.
so once again if I look at the startup of the router
I have login login as the commands with no passwords
and to make the point I'll change the router's names to R1-run
so sh start | i host
shows me that the name of the router in the startup config is R1
but the name of the file in running config is R1-run.
so I can type copy, before I do that once again sh start | b vty
that’s the config in the startup config but if I type copy tftp start
this will overwrite the config in startup config.
I’m gonna specify the running config not the startup config
but I’m gonna over write the startup config with the running config stored on the TFTP server.
So that’s completed.
So if I type sh start | b vty which looked like this previously, notice its changed.
So the startup config has been overwritten with the config on the TFTP server.
Let’s try copying from TFTP to running config
in this case I'll specify the startup config on the TFTP server
but merge that with the running configuration.
Notice as an example that the router name has changed.
sh run | b vty
Some config has remained because it’s done a merged.
So as an example notice the passwords are still showing on the VTY lines
where’s in this config file that we copied
there were no passwords specified on the VTY lines.
So a copy from TFTP to startup is an override of NVRAM
or replacement of a saved configuration
but a copy from TFTP to running config is a merge of the configuration.
Now we could have done configure replace tftp
but I need to specify the IP address of the TFTP server
and the file name that I’m gonna use
and that will now replace the running config
and you can see as an example that commands have been rolled back.
So now if you type sh run | b vty
notice the password have been removed from the running config.
So in summary copy run to start is an override
a startup config with running config
a copy from startup config to running config is a merge not an override
When you configure through the terminal by using configure terminal
that’s a merge of configurations, copy TFTP to run is a merge
you can backup your configs and you should to TFTP servers.
So copy run to tftp or copy start to tftp.
erase start erases the startup-config
so essentially removes it and the router is set back to defaults.
So we'll do that as a last test
erase startup-config hit enter to confirm.
startup config has been erased
I’m gonna reload and not save the configuration
and what will happen now is the router will reboot with no configuration
If you’re not interested in seeing this skip ahead
but otherwise I'm gonna show you the boot process on this router
and show you that it's starts up again
asking us to complete the initial configuration dialogue.
You can see once again that this is a 1841 router
it's decompressing the image at the moment.
We can see the system bootstrap version which is different to the main IOS
It's now booting the IOS, which is this version of software.
We can see router platform, amount of memory, interfaces in the router
amount of NVRAM, size of flashcard and once again size of RAM
so running config is stored in RAM, startup config is stored in NVRAM
and the IOS image is stored on flash and then loaded into memory
when the router is booted
It's sending a broadcast into the network
to try and get a network config file, it then tries to get a cisconet.cfg file.
We're asked if we want to enter the initial configuration dialogue.
I've hit no, so we are now at the CLI prompt on the router.
sh start shows me that I have no startup config.
sh run shows me the default configuration on this router.