Thanks for the help with ping (why is it the man pages make so much more sense when I already know what they mean?)
As far as NFS running, ps axu shows 8 processes called [nfsd] running.
I did setup /etc/exports:
where x.x is obviously the values I'm using for the network. I intend to adjust it later so I'm not sharing the entire drive, but for I figured it's easier to do this until I get some kind of results.
iptables is running, and may very well be the problem. I haven't changed anything from the system default. I know I can find out how to add rules from the man pages, but last time I tried to adjust the iptables rules (for the purposes of ssh) I succeeded only in stopping everything from coming in. (Actually I think I was permitting requests from a non-existant address but you can imagine how useless that was).
How should I tell iptables to allow NFS?