The Fedora Legacy project has released yum configs for Fedora Core 4. Currently there are no Fedora Legacy updates for 4, however the latest updates as released by the Fedora Project are available.

You can pick up the config file from:

http://download.fedoralegacy.org/

65e477dda2e852ea5de37cae3ab7d64a2def6259

fedora/4/updates/SRPMS/legacy-yumconf-4-2.fc4.src.rpm
48fd898e50a9c26d3cad870e9c92cd45d6cc1adf

fedora/4/updates/i386/legacy-yumconf-4-2.fc4.noarch.rpm
48fd898e50a9c26d3cad870e9c92cd45d6cc1adf

fedora/4/updates/x86_64/legacy-yumconf-4-2.fc4.noarch.rpm

There were a number of updates in "Testing" for Fedora Core 4 at time of transition to Legacy. The Fedora Legacy Project will examine these and re-release them as updates-testing if they are security related in the daysahead.