第一步、删除不必要的自带软件包
yum remove Deployment_Guide-en-US finger cups-libs cups ypbind
yum remove bluez-libs desktop-file-utils ppp rp-pppoe wireless-tools irda-utils
yum remove sendmail* samba* talk-server finger-server bind* xinetd
yum remove nfs-utils nfs-utils-lib rdate fetchmail eject ksh mkbootdisk mtools
yum remove syslinux tcsh startup-notification talk apmd rmt dump setserial portmap yp-tools
yum groupremove "Mail Server" "Games and Entertainment" "X Window System" "X Software Development"
yum groupremove "Development Libraries" "Dialup Networking Support"
yum groupremove "Games and Entertainment" "Sound and Video" "Graphics" "Editors"
yum groupremove "Text-based Internet" "GNOME Desktop Environment" "GNOME Software Development"
第二步、升级centos系统
yum update #更新系统
yum clean all #清理全部缓存文件
第三步、禁用seLinux
sestatus #先执行看seLinux状态，如果不是disabled，就需要执行下面步骤，否则不要执行
vi /etc/selinux/config
SELINUX=disabled #禁用SeLinux
SELINUX=enforcing #使用SeLinux
第四步、禁止IPV6（执行后需要reboot重启）
vi /etc/modprobe.conf #打开文件，把下面两行加到最后
alias net-pf-10 off
alias ipv6 off
第五步、初始化防火墙
touch /etc/sysconfig/iptables
iptables -F
iptables -X
iptables -Z
service iptables save
service iptables restart
第六步、禁止无用服务
#! /bin/bash
service acpid off
service atd stop
service auditd stop
service avahi-daemon stop
service avahi-dnsconfd stop
service bluetooth stop
service conman stop
service cpuspeed stop
service cups stop
service dnsmasq stop
service dund stop
service firstboot stop
service hidd stop
service httpd stop
service ibmasm stop
service ip6tables stop
service irda stop
service kdump stop
service lm_sensors stop
service mcstrans stop
service messagebus stop
service microcode_ctl stop
service netconsole stop
service netfs stop
service netplugd stop
service nfs stop
service nfslock stop
service nscd stop
service ntpd stop
service oddjobd stop
service pand stop
service pcscd stop
service portmap stop
service psacct stop
service rdisc stop
service restorecond stop
service rpcgssd stop
service rpcidmapd stop
service rpcsvcgssd stop
service saslauthd stop
service sendmail stop
service setroubleshoot stop
service smb stop
service vncserver stop
