What two configuration files are kept on a Cisco device?

The two primary configuration files that are maintained on a Cisco device are the running configuration and the startup configuration.

The running configuration is the current configuration that is in use by the device at any given moment. Any changes made to the configuration while the device is operational are applied to the running configuration immediately. However, these changes are lost if the device is rebooted unless they are saved.

The startup configuration, on the other hand, is the configuration file that is stored in the NVRAM (non-volatile random-access memory) of the device. This file is loaded when the device powers on or is rebooted. To preserve any changes made to the running configuration, users need to use the command to save those changes to the startup configuration.

This understanding is crucial for network administrators when managing device configurations, ensuring that changes persist through reboots and troubleshooting issues related to device configurations.