我之前已经安装了yum-security。我打算通过输入以下命令进行更新：
[root@localhost /]# yum update
Loaded plugins: presto, priorities, refresh-packagekit, security
Skipping security plugin, no data
Setting up Update Process
Resolving Dependencies
Skipping security plugin, no data
--> Running transaction check
---> Package eject.i686 0:2.1.5-17.fc12 set to be updated
---> Package glibc.i686 0:2.11.1-4 set to be updated
---> Package glibc-common.i686 0:2.11.1-4 set to be updated
---> Package glibc-devel.i686 0:2.11.1-4 set to be updated
---> Package glibc-headers.i686 0:2.11.1-4 set to be updated
---> Package gnome-themes.noarch 0:2.28.1-3.fc12 set to be updated
---> Package gtk2.i686 0:2.18.9-3.fc12 set to be updated
---> Package gtk2-immodule-xim.i686 0:2.18.9-3.fc12 set to be updated
---> Package kernel-PAE.i686 0:2.6.32.11-99.fc12 set to be installed
---> Package kernel-PAE-devel.i686 0:2.6.32.11-99.fc12 set to be installed
---> Package kernel-PAEdebug-devel.i686 0:2.6.32.11-99.fc12 set to be installed
---> Package kernel-debug-devel.i686 0:2.6.32.11-99.fc12 set to be installed
---> Package kernel-devel.i686 0:2.6.32.11-99.fc12 set to be installed
---> Package kernel-firmware.noarch 0:2.6.32.11-99.fc12 set to be updated
---> Package kernel-headers.i686 0:2.6.32.11-99.fc12 set to be updated
---> Package libnetfilter_conntrack.i686 0:0.0.101-1.fc12 set to be updated
---> Package media-player-info.noarch 0:5-1.fc12 set to be updated
---> Package nscd.i686 0:2.11.1-4 set to be updated
---> Package perf.noarch 0:2.6.32.11-99.fc12 set to be updated
---> Package rhythmbox.i686 0:0.12.6-5.fc12 set to be updated
---> Package sysvinit-tools.i686 0:2.87-3.dsf.fc12 set to be updated
--> Finished Dependency Resolution
--> Running transaction check
---> Package kernel-PAE.i686 0:2.6.31.12-174.2.3.fc12 set to be erased
--> Finished Dependency Resolution
Dependencies Resolved
================================================================================
Package Arch Version Repository Size
================================================================================
Installing:
kernel-PAE i686 2.6.32.11-99.fc12 updates 20 M
kernel-PAE-devel i686 2.6.32.11-99.fc12 updates 6.2 M
kernel-PAEdebug-devel i686 2.6.32.11-99.fc12 updates 6.2 M
kernel-debug-devel i686 2.6.32.11-99.fc12 updates 6.2 M
kernel-devel i686 2.6.32.11-99.fc12 updates 6.1 M
Updating:
eject i686 2.1.5-17.fc12 updates 49 k
glibc i686 2.11.1-4 updates 4.2 M
glibc-common i686 2.11.1-4 updates 14 M
glibc-devel i686 2.11.1-4 updates 953 k
glibc-headers i686 2.11.1-4 updates 590 k
gnome-themes noarch 2.28.1-3.fc12 updates 1.5 M
gtk2 i686 2.18.9-3.fc12 updates 3.2 M
gtk2-immodule-xim i686 2.18.9-3.fc12 updates 60 k
kernel-firmware noarch 2.6.32.11-99.fc12 updates 968 k
kernel-headers i686 2.6.32.11-99.fc12 updates 749 k
libnetfilter_conntrack i686 0.0.101-1.fc12 updates 37 k
media-player-info noarch 5-1.fc12 updates 32 k
nscd i686 2.11.1-4 updates 189 k
perf noarch 2.6.32.11-99.fc12 updates 79 k
rhythmbox i686 0.12.6-5.fc12 updates 4.0 M
sysvinit-tools i686 2.87-3.dsf.fc12 updates 58 k
Removing:
kernel-PAE i686 2.6.31.12-174.2.3.fc12 @updates 72 M
Transaction Summary
================================================================================
Install 5 Package(s)
Upgrade 16 Package(s)
Remove 1 Package(s)
Reinstall 0 Package(s)
Downgrade 0 Package(s)
Total download size: 75 M
Is this ok [y/N]:
但后来我改变了主意，我决定只进行安全更新而不是完全更新，所以我输入了以下命令：
[root@localhost /]# yum --security update
Loaded plugins: presto, priorities, refresh-packagekit, security
Setting up Update Process
Resolving Dependencies
Limiting packages to security relevant ones
http://download.fedoraproject.org/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.cuhk.edu.hk/pub/linux/fedora/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://ftp.cuhk.edu.hk/pub/linux/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.cuhk.edu.hk/pub/linux/fedora/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://ftp.riken.jp/Linux/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.riken.jp/Linux/fedora/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://mirror.cse.iitk.ac.in/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://mirror.cse.iitk.ac.in/fedora/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://mirrors.isu.net.sa/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://mirrors.isu.net.sa/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
ftp://ftp.chu.edu.tw/linux/Fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno -1] Metadata file does not match checksum
Trying other mirror.
http://mirror.yandex.ru/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://mirror.yandex.ru/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://linus.iyte.edu.tr/linux/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://linus.iyte.edu.tr/linux/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://ftp.jaist.ac.jp/pub/Linux/Fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.jaist.ac.jp/pub/Linux/Fedora/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://ftp.kddilabs.jp/Linux/packages/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://srv2.ftp.ne.jp/Linux/packages/fedora/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://www.ftp.ne.jp/Linux/distributions/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://srv2.ftp.ne.jp/Linux/distributions/fedora/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://ftp.rhd.ru/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.rhd.ru/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://mirrors.163.com/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://mirrors.163.com/fedora/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://mirror.nus.edu.sg/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://mirror.nus.edu.sg/fedora/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://ftp.yz.yamagata-u.ac.jp/pub/linux/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.yz.yamagata-u.ac.jp/pub/linux/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://ftp.linux.org.tr/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.linux.org.tr/fedora/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://mirrors.cytanet.com.cy/linux/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://mirrors.cytanet.com.cy/linux/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://fedoramirror.hnsdc.com/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://fedoramirror.hnsdc.com/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://ftp.twaren.net/Linux/Fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://c147.twaren.net/pub/Linux/Fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://ftp.mirror.tw/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.mirror.tw/pub/fedora/linux/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://ftp.cs.pu.edu.tw/Linux/Fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ftp.cs.pu.edu.tw/Linux/Fedora/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
http://ubuntu.cn99.com/fedora/updates/12/i386/repodata/updateinfo.xml.gz: [Errno 14] HTTP Error 416 : http://ubuntu.cn99.com/fedora/updates/12/i386/repodata/updateinfo.xml.gz
Trying other mirror.
Error: failure: repodata/updateinfo.xml.gz from updates: [Errno 256] No more mirrors to try.
You could try using --skip-broken to work around the problem
^C[root@localhost /]#
从输出中可以看出，当我运行yum --security update命令时，它确实显示了Limiting packages to security relevant ones消息，因此它知道该选项。
但是我不知道为什么一直报http错误416。我在google上搜索，发现了下面的错误描述，但似乎没有多大帮助。
HTTP ERROR 416 - Requested Range Not Satisfiable
A 416 status code indicates that the server was unable to fulfill the request. This may be, for example, because the client asked for the 800th-900th bytes of a document, but the document was only 200 bytes long.
它建议我使用该--skip-broken选项，我尝试过并且输出是相同的。
--security我已经测试了很多次，只是在使用该选项时它不起作用。
这个问题的可能原因是什么？
听起来它只是试图从回购服务器中提取安全数据，但失败了。运行并重
yum clean metadata试。