centos7 内核优化

vi /etc/sysctl.conf

#关闭ipv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
##决定检查过期多久邻居条目
net.ipv4.neigh.default.gc_stale_time=120
##使用arp_announce / arp_ignore解决ARP映射问题
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.all.arp_announce=2
net.ipv4.conf.lo.arp_announce=2
## 避免放大攻击
net.ipv4.icmp_echo_ignore_broadcasts = 1
## 开启恶意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
##关闭sysrq功能
kernel.sysrq = 0
##core文件名中添加pid作为扩展名
kernel.core_uses_pid = 1
## 开启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
##timewait的数量，默认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的速率比内核处理这些包的速率快时，允许送到队列的数据包的最大数目
net.core.netdev_max_backlog = 262144
##限制仅仅是为了防止简单的DoS 攻击
net.ipv4.tcp_max_orphans = 3276800
##未收到客户端确认信息的连接请求的最大值
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_timestamps = 0
##内核放弃建立连接之前发送SYNACK 包的数量
net.ipv4.tcp_synack_retries = 1
##内核放弃建立连接之前发送SYN 包的数量
net.ipv4.tcp_syn_retries = 1
##开启重用。允许将TIME-WAIT sockets 重新用于新的TCP 连接
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_fin_timeout = 1
##当keepalive 起用的时候，TCP 发送keepalive 消息的频度。缺省是2 小时
net.ipv4.tcp_keepalive_time = 1800
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_keepalive_intvl = 15
##允许系统打开的端口范围
net.ipv4.ip_local_port_range = 1024    65000
##修改防火墙表大小，默认65536
net.netfilter.nf_conntrack_max=655350
net.netfilter.nf_conntrack_tcp_timeout_established=1200
## 确保无人能修改路由表
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.default.secure_redirects = 0
#其他
kernel.printk = 5
kernel.threads-max = 1060863
fs.file-max = 5242880
net.core.somaxconn = 65535
net.core.netdev_max_backlog = 16384

sysctl -p