1.单进程打开文件数限制
#ulimit -n 查询当前数值，默认1024
#ulimit -n 65535 设为最大值
2.查看TIME_WAIT状态的命令
#netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S[a]}'
3.内核优化
备份内核文件 mv /etc/sysctl.conf /etc/sysctl.confbak
新建并编辑内核文件 vi /etc/sysctl.conf
写入以下内容：
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net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.icmp_ignore_bogus_error_responses = 1
net.ipv4.ip_forward = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
net.ipv4.tcp_max_tw_buckets = 6000
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_rmem = 4096 87380 4194304
net.ipv4.tcp_wmem = 4096 16384 4194304
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.netdev_max_backlog = 32768
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.tcp_max_syn_backlog = 65536
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_fin_timeout = 30
net.ipv4.tcp_keepalive_time = 1200
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_keepalive_intvl = 15
net.ipv4.ip_local_port_range = 1024 65000
net.netfilter.nf_conntrack_max = 655350
net.netfilter.nf_conntrack_tcp_timeout_established = 1200
-------------------------------------------------------------
保存之后 sysctl -p 刷新内核文件
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#关闭IPV6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
#避免放大攻击
net.ipv4.icmp_echo_ignore_broadcasts = 1
#开启恶意的ICMP错误消息保护
net.ipv4.icmp_ignore_bogus_error_responses = 1
#关闭路由转发
net.ipv4.ip_forward = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
#开启反向路径过滤
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
#处理无源路由的包
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0
#关SysRq功能
kernel.sysrq = 0
#Core文件名添加PID作为扩展名
kernel.core_uses_pid = 1
#开SYN洪水攻击保护
net.ipv4.tcp_syncookies = 1
#修改消息队列长度
kernel.msgmnb = 65536
kernel.msgmax = 65536
#设置最大内存共享段大小bytes
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
#TIME_WAIT的数量默认为180000
net.ipv4.tcp_max_tw_buckets = 6000
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_rmem = 4096 87380 4194304
net.ipv4.tcp_wmem = 4096 16384 4194304
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
#每个网络接口接收数据包速率比内核处理这些包的速率快时允许送到队列数据包的最大数目
net.core.netdev_max_backlog = 32768
#防止简单的DoS攻击
net.ipv4.tcp_max_orphans = 3276800
#未收到客户端确认信息的连接请求最大值
net.ipv4.tcp_max_syn_backlog = 65536
net.ipv4.tcp_timestamps = 0
#内核放弃建立连接之前发送SYNACK包数量
net.ipv4.tcp_synack_retries = 1
#内核放弃建立连接之前发送SYN包数量
net.ipv4.tcp_syn_retries = 1
#开TIME_WAIT快速回收（解决time_wait过多）
net.ipv4.tcp_tw_recycle = 1
#允许将TIME_WAIT Sockets重新用于新TCP连接（解决time_wait过多）
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_fin_timeout = 30 #秒
#当KeepAlive起用的时候TCP发送KeepAlive消息的频度缺省是2小时（可解决close_wait过多）
net.ipv4.tcp_keepalive_time = 1200 #秒
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_keepalive_intvl = 15
#允许系统打开端口范围
net.ipv4.ip_local_port_range = 1024 65000
#修改防火墙的表大小默认65536
net.netfilter.nf_conntrack_max = 655350
net.netfilter.nf_conntrack_tcp_timeout_established = 1200
-------------------------------------------------------------
保存之后 sysctl -p 刷新内核文件