CentOS 7 装好系统一些优化

妖狐艹你老母 2021-09-30 00:16 254阅读 0赞

1、禁用SELINUX

vi /etc/sysconfig/selinux  设置为disabled

2、同步时间  
\*/20 \* \* \* \* /usr/sbin/ntpdate pool.ntp.org > /dev/null 2>&1

3、文件描述符数量修改/etc/security/limits.conf文件，在文件末尾添加  
root soft nofile 65535  
root hard nofile 65535  
\* soft nofile 65535  
\* hard nofile 65535  
还需要修改/etc/security/limits.d下面的conf文件(会覆盖前面的配置信息)，我的是20-nproc.conf  
\* soft nproc 65535  
\* hard nproc 65535

4、禁用自带的Firewalld防火墙  
systemctl stop firewalld.service 关闭  
systemctl display firewalld.service 禁止开启激动

5、yum 安装net-tools epel-release vim

6、修改rc.local可执行权限 chmod +x /etc/rc.d/rc.local

7、内核优化 修改/usr/lib/sysctl.d/00-system.conf里面的内容，增加如下内容  
\#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  
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

\#启用timewait 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

\#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  
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

转载于:https://www.cnblogs.com/harlanzhang/p/9113285.html