/etc/init.d/iptables stop

chkconfig iptables off

cat /etc/selinux/config #查看状态

sed -i 's#SELINUX=enforcing#SELINUX=disabled#g' /etc/selinux/config

setenforce   #关闭selinux

getenforce     #查看selinux状态

useradd oldboy

id oldboy

echo "" | passwd --stdin oldboy && history -c

cd /etc/yum.repos.d/

wget http://mirrors.163.com/.help/CentOS6-Base-163.repo

rpm --import /etc/pki/rpm-gpg/PRM-GPG-KEY*

yum upgrade

yum install sysstat -y  # sysstat软件包，包含监测系统的一组工具

for a in `chkconfig --list | grep "3:on" | awk '{print $1}' | grep -vE "crond|network|sshd|rsyslog"`;do chkconfig $a off; done

cp /etc/ssh/sshd_config /etc/ssh/sshd_config.ori

sed -i 's%#Port 22%Port 52113%' /etc/ssh/sshd_config

sed -i 's%#PermitRootLogin yes%PermitRootLogin no%'

sed -i 's%#PermitEmptyPasswords no%PermitEmptyPasswords no%'

sed -i 's%#UseDNS yes%UseDNS no%' /etc/ssh/sshd_config

egrep "UseDNS|52113|RootLogin|EmptyPass" /etc/ssh/sshd_config

visudo  #相当于编辑/etc/sudoer

cp /etc/sudoers /etc/sudoers.ori

echo "oldboy  ALL=(ALL) ALL" >>/etc/sudoers

tail - /etc/sudoers

echo ' LANG="zh_CN.GB18030"'  >/etc/sysconfig/i18n

source /etc/sysconfig/i18n

echo $LANG

echo '*/5 * * * * /usr/sbin/ntpdate time.windows.com >/dev/null 2>&1' >>/var/spool/cron/root

crontab -l

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

ulimit -n

tail - /etc/security/limits.conf

cp /etc/sysctl.conf /etc/sysctl.conf.`date +"%Y-%m-%d_%H-%M-%S"` #备份

cat>>/etc/sysctl.conf<<EOF

net.ipv4.tcp_timestamps =

net.ipv4.tcp_synack_retries =

net.ipv4.tcp_syn_retries =

net.ipv4.tcp_mem =

net.ipv4.tcp_max_orphans =

net.core.wmem_default =

net.core.rmem_default =

net.core.rmem_max =

net.core.wmem_max =

net.ipv4.tcp_rmem=

net.ipv4.tcp_wmem=

net.core.netdev_max_backlog =

net.core.somaxconn =

net.ipv4.tcp_syncookies=

net.ipv4.tcp_tw_reuse =

net.ipv4.tcp_tw_recycle =

net.ipv4.tcp_fin_timeout=

net.ipv4.tcp_keepalive_time=

net.ipv4.tcp_max_syn_backlog =

net.ipv4.ip_local_port_range =

EOF

cat /etc/sysctl.conf

sysctl -p  #参数生效