I am going to reinstall Ubuntu soon and want to move my wireless passwords I have to the new installation. What do I need to backup to put on the new installation?
As @Alaa mentioned, you'd want to copy your system connections to the new computer. Just doing a quick copy of files from
/etc/NetworkManager/system-connections/ will suffice. If it doesn't work double check that permissions are rw for root only.
If you have any VPN connections, you'd want to do that for
/etc/NetworkManager/VPN as well.
User-specific ones are stuck in your keyring. If you want, you can copy that to a remote location and drop it onto your new system.