Netgear routers save settings, such as your router password and user name, in a configuration file on your computer. This file is saved with the extension "cfg" and, according to Netgear, can be saved to your computer, restore your router's settings or reset your router to factory settings. However, the config file of your old router should not be used with a new router.
Your router settings file contains information that allows you to log in to the router itself. This information is easily changed when you install a new router. However, you may want to use the same wireless settings for the strongest connection. Furthermore, if you use the same network name, password and encryption type, you can allow your devices to continue to access your network without issue. Otherwise, changing the password will require you to re-connect to the network and enter any security information on each device.
Using the Config File
When creating a back-up copy of your settings with Netgear's software, you must log in to your control panel. You can do so by accessing "http://routerlogin.net" from your browser. The "Backup Settings" link under the Maintenance section offers the option to save your current settings. Your specific router may not give you an option of the file name. For example, your router may just use its model number for the name. However, you can choose where to save this file. From this same screen, you can choose to upgrade from the config file by clicking "Browse" and locating it on your computer.
The reason that you should not use a configuration file from your old Netgear router with a new one is because they have different firmware. Firmware is the software that is stored on your router's internal memory. Firmware varies between models, and even two routers that are the same model may have different firmware, if one is more recent. You can update firmware by clicking the "Router Upgrade" link from your Netgear control panel.
You cannot manually extract router information from your config file, even if you open it in a text editor. It may appear as gibberish that is not human-friendly. Instead, if you want to save your settings, you may consider writing them down so that you can manually input the same settings with a new router. Alternatively, you can take a screen capture of the different screens of your current Netgear router, before setting up the new one. You can then use these for reference when setting up the new router.