摘要：
允许新TCP连接net.ipv4.TCP _ tw_ reuse=1net.ipv4.TCP _ mem=945000009150000009270000000net.ipv4 TCP _ fin_ Timeout=1#启用keepalive时，TCP发送keepalive消息的频率。默认值为2小时net.ipv4.tcp _keepalive_Time=30#系统允许打开的端口范围。不建议从1024开始，因为有些端口可能在10000以内。一般来说，这就足够了。
一、在安装的时候配置网卡名称的参数
1. 选择“Install Centos 7” 2. 按Tab，打开kernel启动选项后，增加 net.ifnames=0 biosdevname=0
二、最小化安装完成之后必备安装软件
# 添加epel源，安装基础软件，设置主机名
rpm -ivh http://mirrors.aliyun.com/epel/epel-release-latest-7.noarch.rpm
yum install -y net-tools vim lrzsz tree screen lsof tcp wget tcpdump nc mtr nmap openssl-devel ntpdate
hostnamectl set-hostname linux-node1.example.com
# 关闭firewalld和NetworkManager
systemctl stop firewalld
systemctl stop NetworkManager systemctl disable firewalld systemctl disable NetworkManager
# 关闭selinux
setenforce 0 sed -i '/SELINUX/s/enforcing/disabled/' /etc/selinux/config
# 设置打开文件描述符的数量 echo "* hard nofile 65536" >> /etc/security/limits.conf echo "* soft nofile 65536" >> /etc/security/limits.conf
# 设置记录历史命令的格式
echo 'export HISTTIMEFORMAT=" %F %T `whoami` "' >> /etc/profile
source /etc/profile
# 使用tables键的时候补全systemctl命令
yum install -y bash-completion
# 安装killall命令
yum install -y psmisc
# 时间同步，如果没有内网时间同步可以使用公网的
crontab -e
*/5 * * * * /usr/sbin/ntpdate time1.aliyun.com
三、内核参数优化
cat /etc/sysctl.conf # 系统优化参数 # 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
# 启用timewait 快速回收，需要先打开时间戳。注：（NAT的网络和负载均衡器上不能打开）
net.ipv4.tcp_timestamps = 1
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 # 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 = 30 #允许系统打开的端口范围，不建议从1024开始，因为某些端口会存在10000以内。一般情况下已够用。 net.ipv4.ip_local_port_range = 10000 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