当前系统为CentOS Linux release 6.0 (Final)，内核版本为2.6.32-71.el6.i686.由于最近内核出现最新的漏洞(linux kernel 又爆内存提权漏洞，2.6.39 内核无一幸免，所以将内核升级至3.2.2最新版本。

1. 查看当前系统内核

# uname -r
2 2.6.32-71.el6.i686

2. 下载linux-3.2.2内核包

# cd ~
# wget -c http://www.kernel.org/pub/linux/kernel/v3.0/linux-3.2.2.tar.bz2
# tar jxvf  linux-3.2.2.tar.bz2
# cd linux-3.2.2

3. 配置内核并安装

# make mrproper  #清除环境变量，即清除配置文件
# make menuconfig  #在菜单模式下选择需要编译的内核模块

找到以下选中选项并选中networking support → networking options → network packet filtering framework(netfilter)

(1).Core netfilter configuration

• 勾中”Netfilter connection tracking support” -m state相关模块是依赖它的，不选则没有。
• 将netbios name service protocal support(new) 编译成模块,不然后面升级iptables后启动时会出错
• 勾中“Netfilter Xtables support (required for ip_tables)”

(2).IP: Netfilter Configuration

• 将 “IPv4 connection tracking support (require for NAT)” 编译成模块。
• 勾中IP tables support (required for filtering/masq/NAT) 。
• 将 “Full NAT” 下的 “MASQUERADE target support” 和 “REDIRECT target support” 编译成模块

(3).其它模块可以根据自己的需要进行选择,若不懂可以参考内核配置手册.

# make clean #确保所有东西均保持最新状态.
# make bzImage #生成内核文件
# make modules #编译模块
# make modules_install #安装模块
# make install #安装

4. 编辑 /etc/grub.conf 文件，将 default=1 改为 default=0

# cat /etc/grub.conf

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd0,0)
# kernel /vmlinuz-version ro root=/dev/mapper/VolGroup-lv_root
# initrd /initrd-[generic-]version.img
#boot=/dev/sda
default=1
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS Linux (3.2.2)
root (hd0,0)
kernel /vmlinuz-3.2.2 ro root=/dev/mapper/VolGroup-lv_root rd_LVM_LV=VolGroup/lv_root rd_LVM_LV=VolGroup/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us crashkernel=auto rhgb quiet
initrd /initramfs-3.2.2.img
title centos (2.6.32-71.el6.i686)
root (hd0,0)
kernel /vmlinuz-2.6.32-71.el6.i686 ro root=/dev/mapper/VolGroup-lv_root rd_LVM_LV=VolGroup/lv_root rd_LVM_LV=VolGroup/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us crashkernel=auto rhgb quiet
initrd /initramfs-2.6.32-71.el6.i686.img

5. 重启系统,并查看内核

# reboot
# uname -r
3.2.2