$su
#cd /etc/yum.repos.d
#chmod 777 *.*
#mv *.* /home/bak
#vi a.repo
将如下内容粘入，保存退出（每行前一定不要留有空格）
[releases-mirror.sohu.com]
name=fedora-releases
baseurl=http://mirrors.sohu.com/fedora/releases/15/Fedora/i386/os/
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-Fedora
[everything-mirror.sohu.com]
name=fedora-Everything
baseurl=http://mirrors.sohu.com/fedora/releases/15/Everything/i386/os/
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-Fedora
[updates-mirror.sohu.com]
name=Fedora-updates
baseurl=http://mirrors.sohu.com/fedora/updates/15/i386/
enabled=1
gpgcheck=0
最后执行
#yum makecache