关闭系统不必要的服务；关闭selinux，关闭iptables




关闭系统不必要的服务；关闭selinux，关闭iptables；关闭ctrl+alt+del重启；设置ssh端口，关闭DNS解析；设置系统最大文件描述符；设置系统关键文件权限；配置安装ntp；安装vim；配置安装阿里云yum源和epel源；
















#!/bin/bash

#written by mofansheng@2015-11-03
#system optimization script
#The fllow apply to CentOS 6.x
.  /etc/init .d /functions

function  check_ok(){
  if  [ $? - eq  0 ]
   then
     echo  ""
     continue
  else
     echo  "pls check error"
     exit
  fi
}

cat <<EOF
-----------------------------------------------------------------------
|                     system optimization                             |
-----------------------------------------------------------------------
EOF

#close unimportant system services
echo  "===Close unimportant system services,it will take serval mintinues==="
for  s  in  `chkconfig --list| grep  3:on| awk  '{print $1}' | grep  -Ev  "crond|sshd|sysstat|rsyslog|network" `
do
  chkconfig $s off
done
check_ok
action  "Close unimportant system services"  /bin/true


#close selinux
echo  "===close SELINUX==="
if  [ `getenforce` !=  "Disabled"  ]
then
 sed  -i  's/SELINUX=enforcing/SELINUX=disabled/g'  /etc/selinux/config
 echo  "selinux is disabled,you must reboot!"
else
 action  "SELINUX is closed"  /bin/true
fi
check_ok
action  "Close SELINUX"  /bin/true


#close ctrl+alt+del
mv  /etc/init/control-alt-delete .conf  /etc/init/control-alt-delete .conf.bak


#close iptables
echo  "===close iptables==="
iptables-save > /etc/sysconfig/iptables_ $( date  +%s)
iptables -F
service iptables save
check_ok
action  "iptables is closed"  /bin/true


#set ulimit
echo  "ulimit -SHn 65535"  >> /etc/rc . local

#set SSH
sed  -i  's/#UseDNS yes/UseDNS no/g'  /etc/ssh/sshd_config
sed  -i  's/#Port 22/Port 65500/g'  /etc/ssh/sshd_config
service sshd restart


#set system files permission
chmod  600  /etc/passwd
chmod  600  /etc/group
chmod  600  /etc/shadow
chmod  600  /etc/gshadow


#set ntp
yum  install  ntpdate -y
ntpdate ntp.fudan.edu.cn
echo  "* 3 * * * /usr/sbin/ntpdate ntp.fudan.edu.cn >/dev/null 2>&1"  >> /etc/crontab
service crond restart
check_ok
action  "ntpdate is installed and add in crontab"  /bin/true


#set vim
echo  "===install vim,it will take serval mintinues==="
yum  install  vim-enhanced -y &> /dev/null
alias  vi =vim
echo  "alias vi=vim"  >> /root/ .bashrc
check_ok
action  "vim is installed"  /bin/true


#set yum repos
echo  "===update yum repos,it will take serval mintinues==="
yum  install  wget -y
mv  /etc/yum .repos.d /CentOS-Base .repo  /etc/yum .repos.d /CentOS-Base .repo.bak
wget -O  /etc/yum .repos.d /CentOS-Base .repo http: //mirrors .aliyun.com /repo/Centos-6 .repo &> /dev/null
wget -O  /etc/yum .repos.d /epel .repo http: //mirrors .aliyun.com /repo/epel-6 .repo &> /dev/null
yum clean all &> /dev/null
yum makecache &> /dev/null
check_ok
action   "yum repos update is ok"  /bin/true