Automated Backup of IOS Router Configuration

Who hasn't had the experience of remoting to a router and making a configuration change... and not saving that change. Inevitably that is the weekend that facility will experience a power outage long enough to deplete their UPS. And then you get that dreaded text message from NetOps that a facility is down. Argh! Fortunately Cisco IOS 12.x and later supports a cron like service known as "kron". One of the handiest uses for kron is to configure automatic backup of the router's configuration to a TFTP server.

kron occurrence backup at 0:00 Thu recurring
 policy-list backup
!
kron policy-list backup
 cli write
 cli show running-config | redirect tftp://192.168.1.38/brtgate.config
!

This creates a batch of commands named "backup" [where in typical ISO fashion everything is referred to as a "policy"] that will be executed every Thursday morning. This batch commits the running configuration to flash memory ["cli write"] and copies the running configuration to the specified TFTP server ["cli show running-config | redirect tftp://192.168.1.38/brtgate.config"]. The rather odd looking use of "redirect" is because the IOS "copy" command is interactive and interactive commands cannot be run via "kron".

Remember that the file on the TFTP server has to exist, even if zero sized, and be world writable; otherwise the redirect will fail with a permission denied error.