Most systems set a default umask of 0022, which produce directories with 755 permissions (= 777 & 022, "&" = bitwise AND) and files with 644 permissions (= 666 & 022). If you type "umask" with no arguments, it will show you what your current umask is. If it's already 0022 (or 022), then the permissions are being forced by the remote server (SMB/CIFS probably?) and there's nothing you can do about it other than change them manually.