centos下epel源可直接安装：
yum install rtorrent配置文件.rtorrent.rc ：
#下载时每个种子的最大连接数
min_peers = 1
max_peers = 500
#种子下载完成后每个种子最大连接数，-1等同于上面下载时连接数
min_peers_seed = -1
max_peers_seed = -1
#全局最大上传和下载连接数
max_uploads_global = 0
max_downloads_global = 0
#每个种子最大上传和下载连接数
max_uploads = 200
max_downloads = 200
#上传/下载限速，0为不限制
download_rate = 0
upload_rate = 0
check_hash = no
directory = /root/download
session = /root/session
port_random = yes
port_range = 6998-10000
#外出连接加密，如果连接失败转为不加密重试，允许进入连接加密，同时还允许未加密连接进入
#protocol.encryption.set = allow_incoming,try_outgoing,enable_retry
#只允许进入、外出连接加密和内容加密
protocol.encryption.set = require
#进入、外出连接和内容都必须加密
#protocol.encryption.set = require,require_RC4
encoding_list = utf-8
dht = off
peer_exchange = no
use_udp_trackers = yes
#log.open_file = "rtorrent.log", (cat,/tmp/rtorrent.log)
#log.add_output = "debug", "rtorrent.log"
#当删除任务时同时删除下载的文件
method.set_key = event.download.erased,delete_erased,"execute=rm,-rf,--,$d.base_path="
schedule = low_diskspace,5,60,close_low_diskspace=100M
schedule = watch_directory,5,5,load_start=/root/watch/*.torrent在tmux或screen窗口内启动：
mkdir session download watch
rtorrent将种上传到watch目录自动开始下载，在管理窗口通过上下左右方向键可查看详细信息。
ctrl+q退出，ctrl+d暂停，再按ctrl+d删除，ctrl+s开始。
加密的相关参数，多个值应该和iptables规则相似，从左到右匹配，默认不处理。
# Encryption options, set to none (default) or any combination of the following:
# allow_incoming: allow incoming encrypted connections
# try_outgoing: use encryption for outgoing connections
# require: disable unencrypted handshakes
# require_RC4: also disable plaintext transmission after the initial encrypted handshake
# enable_retry: if the initial outgoing connection fails, retry with encryption turned on if it was off or off if it was on
# prefer_plaintext: choose plaintext when peer offers a choice between plaintext transmission and RC4 encryption, otherwise RC4 will be used