此脚本用于新装CentOS的相关配置工作，比如禁掉iptable和SElinux及ipv6，优化系统内核，停掉一些没必要启动的系统服务等此脚本尤其适全大批新安装的CentOS 5.X系列的服务器，脚本代码如下所示（此脚本在Centos5.5_x64下已通过）：。
#!/bin/bash # Created by kerryhu # MAIL:king_819@163.com # BLOG:http://kerry.blog.51cto.com
cat << EOF +————————————————————–+ | === Welcome to Centos System init === |
+————————————————————–+ +————————–by kerry—————————-+
EOF #set ntp yum -y install ntp echo “* 3 * * * /usr/sbin/ntpdate 210.72.145.44 > /dev/null 2>&1” >> /etc/crontab
service crond restart #set ulimit echo “ulimit -SHn 102400” >> /etc/rc.local #set locale
#true > /etc/sysconfig/i18n #cat >>/etc/sysconfig/i18n<
#SYSFONT=”latarcyrheb-sun16″ #EOF #set sysctl true > /etc/sysctl.conf cat >> /etc/sysctl.conf << EOF
net.ipv4.ip_forward = 0 net.ipv4.conf.default.rp_filter = 1 net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0 kernel.core_uses_pid = 1 net.ipv4.tcp_syncookies = 1 kernel.msgmnb = 65536
kernel.msgmax = 65536 kernel.shmmax = 68719476736 kernel.shmall = 4294967296 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 net.core.netdev_max_backlog = 262144
net.core.somaxconn = 262144 net.ipv4.tcp_max_orphans = 3276800 net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_timestamps = 0 net.ipv4.tcp_synack_retries = 1 net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_tw_recycle = 1 net.ipv4.tcp_tw_reuse = 1 net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_fin_timeout = 1 net.ipv4.tcp_keepalive_time = 1200 net.ipv4.ip_local_port_range = 1024 65535
EOF /sbin/sysctl -p echo “sysctl set OK!!” #close ctrl+alt+del sed -i “s/ca::ctrlaltdel:/sbin/shutdown -t3 -r now/#ca::ctrlaltdel:/sbin/shutdown -t3 -r now/” /etc/inittab
#set purview chmod 600 /etc/passwd chmod 600 /etc/shadow chmod 600 /etc/group chmod 600 /etc/gshadow
#disable ipv6 cat << EOF +————————————————————–+
| === Welcome to Disable IPV6 === | +————————————————————–+
EOF echo “alias net-pf-10 off” >> /etc/modprobe.conf echo “alias ipv6 off” >> /etc/modprobe.conf
/sbin/chkconfig –level 35 ip6tables off echo “ipv6 is disabled!” #disable selinux sed -i /SELINUX/s/enforcing/disabled/ /etc/selinux/config
echo “selinux is disabled,you must reboot!” #vim sed -i “8 s/^/alias vi=vim/” /root/.bashrc
echo syntax on > /root/.vimrc #zh_cn sed -i -e s/^LANG=.*/LANG=”en”/ /etc/sysconfig/i18n
#init_ssh ssh_cf=”/etc/ssh/sshd_config” sed -i -e 74 s/^/#/ -i -e 76 s/^/#/ $ssh_cf #sed -i “s/#Port 22/Port 65535/” $ssh_cf
sed -i “s/#UseDNS yes/UseDNS no/” $ssh_cf #client sed -i -e 44 s/^/#/ -i -e 48 s/^/#/ $ssh_cf
service sshd restart echo “ssh is init is ok…………..” #chkser #tunoff services
#——————————————————————————– cat << EOF
+————————————————————–+ | === Welcome to Tunoff services === |
+————————————————————–+ EOF #———————————————————————————
for i in `ls /etc/rc3.d/S*` do CURSRV=`echo $i|cut -c 15-` echo $CURSRV
case $CURSRV in crond | irqbalance | microcode_ctl | network | random | sshd | syslog | local )
echo “Base services, Skip!” ;; *) echo “change $CURSRV to off”
chkconfig –level 235 $CURSRV off service $CURSRV stop ;; esac
done echo “service is init is ok…………..”