[K12OSN] non-terminal clients getting DHCP, but no access

[ssh at tranquility.net]

Both of the suggestions looked good, on iptables and verifying NAT. I 
restarted NAT, it did not help. Looking at Iptables seemed promising, I 
also had a chain that allowed lo but not eth0. I closed the lo chain, 
edited it (via Webmin) to accept eth0 and put it at the top.

That didn't work, so I created a new rule and placed it above the default 
rule, still no joy. I then turned off the firewall completely from System 
--> Administration--> Security Level and Firewall. (Selinux was already 
disabled). It _still_ doesn't work on the non-clients (thin clients are 
fine). This leads me to believe that it's not a firewall issue. 
Suggestions?
TIA
Scott S.