apt-get update를 하는 경우 아래 오류가 발생 Err:6 http://deb.debian.org/debian stretch/main amd64 Packages 404 Not Found Err:8 http://deb.debian.org/debian stretch-updates/main amd64 Packages 404 Not Found 15:54:34 Ign:1 http://deb.debian.org/debian stretch InRelease 15:54:34 Ign:2 http://deb.debian.org/debian stretch-updates InRelease 15:54:34 Ign:3 http://deb.debian.org/debian stretch Release 15:54:34 Ign..