|  | 6.1 | Router Configuration Files
| 6.1.1 | Router configuration file information
In this section, you will learn how to work with configuration files that can come from the console, NVRAM, or TFTP server. A router uses the following information from the configuration file when it starts up: Cisco IOS software version Router identification Boot file locations Protocol information Interface configurations The configuration file contains commands to customize router operation. The router uses this information when it starts up. If there is no configuration file available, the system configuration dialog setup guides you through the process of creating one.