After my ordeal with the network (I wasn't getting a default gateway because the network files were not being written out properly by system-config-network when choosing dhcp), I found another config tool that doesn't do what it's supposed to: system-config-securitylevel. I was trying to get nfs working, and though I had nfs and portmap ports open, I figured from rpcinfo -p that I also needed the mountd ports open. So I tried to add them in system-config-securitylevel, but iptables remained unchanged. Had to insert the rules manually, iptables-save, etc. I'm surprised I don't see other people discovering non-working configuration tools. Is there something wrong with my gnome installation? Or does everybody else configure stuff at the prompt? At any rate, maybe gnome10 was not ready for prime time.
