I had already installed the yum-security before. And I was going to do an update by entering the following command:

[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]:

But then I changed my mind, I decided to do a security-only update instead of a full update, so I entered the following command:

[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 /]#

As it can be seen in the output, when I run the yum --security update command, it did show the Limiting packages to security relevant ones message so it's aware of the option.

But I don't know why it keeps reporting the http error 416. I searched in google and found the following description of the error but it doesn't seem to help much.

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.

It suggests me to use the --skip-broken option, I tried and the output is the same.

I already tested many times, it just doesn't work when the --security option is used.

What could be the possible cause for this problem?