CentOS 7 网络优化，TCP/IP、Socket参数调优

使用vi编辑器打开“sysctl.conf”文件

vi /etc/sysctl.conf

添加/修改以下参数：

# 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
kernel.shmmax = 68719476736
kernel.shmall = 4294967296

# TIME_WAIT套接字的最大数量
net.ipv4.tcp_max_tw_buckets = 6000

# 使用Selective ACK
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1

# TCP读写buffer优化
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

# 数据包最大设备队列
net.core.netdev_max_backlog = 262144

# 防止简单的Dos攻击
net.ipv4.tcp_max_orphans = 3276800

# SYN队列的长度
net.ipv4.tcp_max_syn_backlog = 262144

# 禁用时间戳
net.ipv4.tcp_timestamps = 0

# 放弃建立连接之前发送的SYNACK包数量
net.ipv4.tcp_synack_retries = 1

# 放弃建立连接之前发送的SYN包数量
net.ipv4.tcp_syn_retries = 1

# 启用TIME-WAIT sockets快速回收
net.ipv4.tcp_tw_recycle = 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

# TCP发送keepalive消息的频度
net.ipv4.tcp_keepalive_time = 30

# 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