firewalls besides iptables

[Margaret Doll]

I have opened some ports in iptables on an Enterprise 3 system to allow 
nfs mounting of its partitions on other systems.  When I do an "nmap" 
on this system from a second system, I see that some of the ports that 
I thought I had opened are closed and some are open.

Is there something besides iptables that might be running on the system?
	I did not set up the "problem" system, so I do not know all the steps 
that were involved in the setup.  Other Enterprise 3 systems that I 
have do have these "closed" ports open.

nfs is not working properly on the first  system.  It does work if I 
stop the iptables services altogether.

The other "strange" thing about the system is that "rpcinfo -p"  shows 
portmapper, rquotad, nfs, mountd and status.  nlockmgr and sgi_fam are 
not present.  Services portmap, nfs and nfslock have been started.