After you have installed Fedora core, it’s time to setup Fedora Repository
# mkdir /sources
# mkdir /sources/fc9
Assume that your Fedora9 DVD is at /media/FC9/Packages
Please note, all you need is only the Packages folder that contains all of RPMS files.
# cd /media/FC9/Packages
# cp -v * /sources/fc9/
# cd /sources/fc9/ && rpm -ivh createrepo*
# createrepo /sources/fc9
At this step, please wait several minute for system to list all files.
taken from http://en.wikipedia.org/wiki/DomainKeys
DomainKeys is an e-mail authentication system designed to verify the DNS domain of an e-mail sender and the message integrity. The DomainKeys specification has adopted aspects of Identified Internet Mail to create an enhanced protocol called DomainKeys Identified Mail (DKIM). This merged specification is the basis for an IETF Working Group which guided the specification toward becoming an IETF standard.
The DKIM standard was issued in May 2007. The DomainKeys draft was also issued under “historical” status at the same time.