CentOS不能上网时，配置本地yum源的方法

1.先挂载iso镜像：
1）创建挂载目录：mkdir /mnt/cdrom (如有此目录，请忽视此步。)
2）挂载：mount -o loop rhel-server-5.4-i386-dvd.iso /mnt/cdrom

2.配置yum本地源：
在/etc/yum.repos.d/下创建文件：name.repo
加入如下内容
[name]
name=install name
baseurl=file:///mnt/cdrom
enabled=1
gpgcheck=0

3.禁用默认的yum远程源：
vi /etc/yum.repos.d/CentOS-Base.repo

将里面每个子源加个enabled=0
[base]
name=CentOS-$releasever - Base
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5

#released updates
[updates]
name=CentOS-$releasever - Updates
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
#baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/
gpgcheck=1
enabled=0
...

4.执行yum命令，如：
yum install subversion