> First, accessing the printer panel from the system settings was
> useless. No printer could be detected.
I had to run from XFCE Desktop (then System > Administration > Printing)
to setup my networked JetDirect printer. In my case I had to let the firewall
be modified in order to see the printer. Once the printer had been set up,
then it was available to both XFCE and GNOME.
[To get XFCE, do something like "yum install @XFCE-DESKTOP",
logout, then choose "XFCE session" when logging back in.
GDM lets you choose GNOME vs XFCE at each login, and the choice
persists until explicit change.]