1、关闭Selinux
2、清空防火墙并设置基本规则
3、添加user用户并进行Sudo授权管理(根据需求添加自己的用户)
4、禁用Root远程登录
5、禁用不使用的自启动服务
6、删除不使用的系统用户
7、关闭重启组合键(ctl-alt-delete)
8、调整文件描述符大小
9、修改系统显示信息
10、修改历史记录
11、同步系统时间
12、内核参数优化
[root@localhost ~]# vi optimizing.sh
#!/bin/bash
cat << EOF
+---------------------------------------+
| Start Optimize ...... |
+---------------------------------------+
EOF
########## Shut selinux ##########
sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config
echo "Shut selinux. [ OK ]"
########## Set firewall ##########
/sbin/iptables -F
/sbin/iptables -I INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
/sbin/iptables -A INPUT -p tcp --dport 80 -j ACCEPT
/sbin/iptables -A INPUT -p tcp --dport 22 -j ACCEPT
/sbin/iptables -A INPUT -p tcp --dport 53 -j ACCEPT
/sbin/iptables -A INPUT -p udp --dport 53 -j ACCEPT
/sbin/iptables -A INPUT -p udp --dport 123 -j ACCEPT
/sbin/iptables -A INPUT -p icmp -j ACCEPT
/sbin/iptables -P INPUT DROP
/etc/init.d/iptables save > /dev/null 2>&1
echo "Set firewall. [ OK ]"
########## Auth and add user ##########
/usr/sbin/useradd user > /dev/null 2>&1 #添加user用户并设置密码123.com
if [[ $? -eq 0 ]];then
echo "123.com" | passwd --stdin user > /dev/null 2>&1
sed -i "99 s/^/user ALL=(ALL) ALL/" /etc/sudoers
echo "Auth and add user. [ OK ]"
else
echo "User already exist! [Fail]"
fi
########## Shut root login ##########
sed -i "s/#PermitRootLogin yes/PermitRootLogin no/g" /etc/ssh/sshd_config
sed -i "s/#PermitEmptyPasswords no/PermitEmptyPasswords no/g" /etc/ssh/sshd_config
sed -i "s/#UseDNS yes/UseDNS no/g" /etc/ssh/sshd_config
echo "Shut root login. [ OK ]"
########## Forbidden not use service ##########
/sbin/chkconfig auditd off
/sbin/chkconfig blk-availability off
/sbin/chkconfig ip6tables off
/sbin/chkconfig lvm2-monitor off
/sbin/chkconfig netfs off
/sbin/chkconfig udev-post off
echo "Forbidden not use service. [ OK ]"
########## Delete not use user ##########
/usr/sbin/userdel adm > /dev/null 2>&1
/usr/sbin/userdel lp > /dev/null 2>&1
/usr/sbin/userdel shutdown > /dev/null 2>&1
/usr/sbin/userdel halt > /dev/null 2>&1
/usr/sbin/userdel uucp > /dev/null 2>&1
/usr/sbin/userdel operator > /dev/null 2>&1
/usr/sbin/userdel games > /dev/null 2>&1
/usr/sbin/userdel gopher > /dev/null 2>&1
if [[ $? -eq 0 ]];then
echo "Delete not use service. [ OK ]"
else
echo "Not use user already deleted! [Fail]"
fi
########## Shut reboot combination key ##########
sed -i 's#exec /sbin/shutdown -r now#\#exec /sbin/shutdown -r now#' /etc/init/control-alt-delete.conf
echo "Shut reboot combination key. [ OK ]"
########## Modify file descriptor size ##########
echo "* soft nofile 102400" >> /etc/security/limits.conf
echo "* hard nofile 102400" >> /etc/security/limits.conf
echo "Modify file descriptor size. [ OK ]"
########## Modify system show message ##########
echo "Welcome to Server." >/etc/issue
echo "Welcome to Server." >/etc/redhat-release
echo "Modify system show message. [ OK ]"
########## Modify history ##########
sed -i "s/HISTSIZE=1000/HISTSIZE=10/g" /etc/profile
source /etc/profile
echo "Modify history. [ OK ]"
########## Sync timezone ##########
yum install ntp -y > /dev/null 2>&1
cp -rf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
/usr/sbin/ntpdate cn.pool.ntp.org > /dev/null 2>&1
/sbin/hwclock -w
echo "0 * * * * /usr/sbin/ntpdate cn.pool.ntp.org ; hwclock -w" >> /etc/crontab
echo "Sync timezone. [ OK ]"
########## Kernel optimize ##########
cat >> /etc/sysctl.conf << EOF
net.ipv4.tcp_fin_timeout = 2
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.ip_local_port_range = 4096 65000
net.ipv4.tcp_max_tw_buckets = 5000
net.ipv4.tcp_max_syn_backlog = 4096
net.core.netdev_max_backlog = 10240
net.core.somaxconn = 2048
net.core.wmem_default = 4096000
net.core.rmem_default = 4096000
net.core.rmem_max = 4096000
net.core.wmem_max = 4096000
net.ipv4.tcp_synack_retries = 2
net.ipv4.tcp_syn_retries = 2
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.tcp_mem = 94500000 915000000 927000000
EOF
echo "Kernel optimize. [ OK ]"
cat << EOF
+---------------------------------------+
| Optimize the end ...... |
| Please reboot your system ! |
+---------------------------------------+
EOF
13、禁止使用Ctrl+Alt+Del快捷键重启服务器
cp /etc/inittab /etc/inittabbak
vi /etc/inittab #注释掉下面这一行
#ca::ctrlaltdel:/sbin/shutdown -t3 -r now
14、使用yum update更新系统时不升级内核,只更新软件包
注意:由于系统与硬件的兼容性问题,有可能升级内核后导致服务器不能正常启动,这是非常可怕的,没有特别的需要,建议不要随意升级内核。
cp /etc/yum.conf /etc/yum.confbak
修改yum的配置文件 vi /etc/yum.conf 在的最后添加 exclude=kernel*
直接在yum的命令后面加上如下的参数:
yum --exclude=kernel* update
查看系统版本 cat /etc/issue
查看内核版本 uname –a
15、关闭Centos自动更新
chkconfig --list yum-updatesd #显示当前系统状态
yum-updatesd 0:关闭 1:关闭 2:启用 3:启用 4:启用 5:启用 6:关闭
service yum-updatesd stop #关闭 开启参数为start
停止 yum-updatesd: [确定]
service yum-updatesd status #查看是否关闭
yum-updatesd 已停
chkconfig --level 35 yum-updatesd off #禁止开启启动(系统模式为3、5)
chkconfig yum-updatesd off #禁止开启启动(所有启动模式全部禁止)
chkconfig --list yum-updatesd #显示当前系统状态
yum-updatesd 0:关闭 1:关闭 2:启用 3:关闭 4:启用 5:关闭 6:关闭