I'm running F17 from Terminal. I was wondering what is happening in the background when I
yum install packagename. Is that package being searched for on my browser? Where is it being downloaded from? Is that a default location?
If you look in the directory
/etc/yum.repos.d you will see your yum repositories.
You will probably see something like
mirrorlist=http://blah.blah.blah.org associated with each repository.
For each repository, yum will go to the associated mirrorlist to find a URL for downloading the package. In theory, it will find the mirror closest to you.
If you haven't modified anything, then the mirrorlist are default locations, but the actual mirrors could change from time to time.