安装linux系统后调优及安全设置

环境说明

[root@server1 ~]# cat /etc/redhat-release 
CentOS release 6.9 (Final)
[root@server1 ~]# uname -r
2.6.32-696.el6.x86_64

1、更改yum源:

mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup        <<-备份系统自带yum源
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo  <<—国内使用阿里云yum源速度比较快
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-6.repo

注:镜像官方网址http://mirrors.aliyun.com/

如有自建yum仓可以更改成自建yum仓地址信息

2、关闭selinux

永久关闭(需要重启系统)
sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config

临时关闭(无需重启)
setenforce 0  
数字0表示Premissive,即给出警告提示,不会阻止操作,相当于disabled
数字1表示Enfocing,即表示SELinux为开启状态

getenforce      <<-查看selinux当前状态

3、关闭iptables

/etc/init.d/iptables stop          <<-关闭iptables服务
/etc/init.d/iptables status        <<-查看iptables状态
chkconfig iptables off              <<—开机启动关闭

4、精简开机启动

chkconfig|egrep -v "crond|sshd|network|rsyslog|sysstat"|awk '{print "chkconfig",$1,"off"}'|bash       <<-关闭服务
chkconfig --list|grep 3:on       <<-检查开机启动的服务

5、更改字符集(选做)

cp /etc/sysconfig/i18n /etc/sysconfig/i18n.ori
echo 'LANG="zh_CN.UTF-8"'  >/etc/sysconfig/i18n 
source /etc/sysconfig/i18n
echo $LANG

6、普通用户提权(mmod)

useradd mmod
echo 123456|passwd --stdin mmod
cp /etc/sudoers /etc/sudoers.ori
echo "mmod  ALL=(ALL) NOPASSWD: ALL " >>/etc/sudoers
tail -1 /etc/sudoers
visudo -c

7、时间同步

echo '#time sync by mmod at 2015-2-1' >>/var/spool/cron/root
echo '*/5 * * * * /usr/sbin/ntpdate time.nist.gov >/dev/null 2>&1' >>/var/spool/cron/root
crontab -l

注:集群中有时间服务器,更改成时间服务器地址

8、命令行安全(选配)

设置闲置账号超时时间
echo 'export TMOUT=300' >>/etc/profile

命令行历史记录数
echo 'export HISTSIZE=5' >>/etc/profile
echo 'export HISTFILESIZE=5' >>/etc/profile
tail -3 /etc/profile
./etc/profile

9、加大文件描述

echo '*               -       nofile          65535' >>/etc/security/limits.conf 
tail -1 /etc/security/limits.conf 

10、内核优化

cat >>/etc/sysctl.conf<<EOF
net.ipv4.tcp_fin_timeout = 2
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_keepalive_time = 600
net.ipv4.ip_local_port_range = 4000    65000
net.ipv4.tcp_max_syn_backlog = 16384
net.ipv4.tcp_max_tw_buckets = 36000
net.ipv4.route.gc_timeout = 100
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_synack_retries = 1
net.core.somaxconn = 16384
net.core.netdev_max_backlog = 16384
net.ipv4.tcp_max_orphans = 16384
#以下参数是对iptables防火墙的优化,防火墙不开会提示,可以忽略不理。
net.nf_conntrack_max = 25000000
net.netfilter.nf_conntrack_max = 25000000
net.netfilter.nf_conntrack_tcp_timeout_established = 180
net.netfilter.nf_conntrack_tcp_timeout_time_wait = 120
net.netfilter.nf_conntrack_tcp_timeout_close_wait = 60
net.netfilter.nf_conntrack_tcp_timeout_fin_wait = 120
EOF    
sysctl –p       <<-配置完成后查看

11、下载安装基础软件

yum install lrzsz nmap tree dos2unix nc -y

12、定时清理邮件服务临时目录垃圾文件

centos 5版本
find /var/spool/clientmqueue/ -type f | xargs rm -f

centos 6.x版本
find /var/spool/postfix/maildrop/ -type f | xargs rm -f

写成脚本,做定时任务
mkdir -p /server/scripts/
echo "find /var/spool/postfix/maildrop/ -type f | xargs rm -f " > /server/scripts/del_mailfile.sh

echo "00 00 * * * /bin/bash  /server/scripts/del_mailfile.sh > /dev/null  2>&1"

  

 

 

 

可可西里
原文地址:https://www.cnblogs.com/hanyuke/p/7876040.html