net.ipv4.tcp_syncookies = 1 #开启SYN Cookies
net.ipv4.ip_local_port_range = 1025 65534 # 端口
net.ipv4.tcp_max_tw_buckets = 5000 #系统同时保持TIME_WAIT套接字的最大数量
net.ipv4.tcp_fin_timeout = 30 #如果套接字由本端要求关闭，这个参数决定了它保持在FIN-WAIT-2状态的时间
net.ipv4.tcp_keepalive_time = 1200 #keepalive启用时，发送keepalive的频度
net.ipv4.tcp_max_syn_backlog = 8192 #向外连接的端口范围
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_tw_reuse = 1 #开启重用
net.ipv4.tcp_tw_recycle = 0 #快速回收