yes, there is a way.
The server information is stored in the repo file for whatever repository that you are using.
For example, the standard fedora repository is in the fedora.repo file, updates is in the fedora-updates.repo file and the testing updates is in the fedora-updates-testing.repo file. These files are located in /etc/yum.repos.d
You can specify whatever server you wish to use in the baseurl line in the repo file. (If you wish to force it to use only that server, then you need to comment out the mirror url, and uncomment the baseurl lines)
Here is the fedora.repo file for F16
Code:
[fedora]
name=Fedora $releasever - $basearch
failovermethod=priority
#baseurl=http://download.fedoraproject.org/pub/fedora/linux/releases/$releasever/Everything/$basearch/os/
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=fedora-$releasever&arch=$basearch
enabled=1
metadata_expire=7d
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-$basearch
[fedora-debuginfo]
name=Fedora $releasever - $basearch - Debug
failovermethod=priority
#baseurl=http://download.fedoraproject.org/pub/fedora/linux/releases/$releasever/Everything/$basearch/debug/
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=fedora-debug-$releasever&arch=$basearch
enabled=0
metadata_expire=7d
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-$basearch
[fedora-source]
name=Fedora $releasever - Source
failovermethod=priority
#baseurl=http://download.fedoraproject.org/pub/fedora/linux/releases/$releasever/Everything/source/SRPMS/
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=fedora-source-$releasever&arch=$basearch
enabled=0
metadata_expire=7d
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-$basearch
If the baseurl line is uncommented and the mirrorlist line is commented, then it would force yum to always use the download.fedoraproject.org server to download updates from. (The # at the beginning of a line means that line is a comment.)
While forcing it to use a specific server means that if the server isn't available, then your update will fail. It also isn't a good idea to force a specific server because that places more stress on the server itself. It can't "load balance" requests by sending you off to a mirror site based on usage. But sometimes it is necessary to force it so the option is there to do so.