[K12OSN] NX works great . . . mostly!

[Dr. Daniel Loomis]

After some more fiddling with nx I found that iptables is blocking 
connections to my server at work when attempting to access from home.  
The server is behind a fortigate firewall.  The server is running 
K12LTSP 4.1 (Fedora 3) with iptables running as a second layer of 
security.  

I have port 22 opened and can log into the server from home using 
pub/private-key.  When I try to access it with nxclient it logs in ok, 
authenticates, but then times out without ever negotiating an 
X-connection.  If I turn iptables off on the server (using a remote ssh 
console),  I can make the connection just fine.  I configured nx to use 
port 22 in /etc/nxserver/node.conf, but evidently it is still being 
blocked by iptables.

I am using ssl to encrypt the connection over the Internet, which works 
fine so long as iptables is turned off.

What setting do I need to add to  iptables to allow nx traffic to pass 
through?

Dan