NAT and anti spoofing

["Daniel F. Chief Security Engineer -" <danielf@supportteam.net>]

This may be a stupid question but the answer is eluding me right now. 

With NAT setup. 

I have a single machine with 8 global IPs NATed to 8 10.0.0.0/8 IPs. How do 
you filter the 10.0.0.0/8 network from talking to the machines behind the 
firewall. From outside the firewall on the internet.  

I used command like this to get the NAT working is this right. 
iptables -t nat -A POSTROUTING -s 10.10.10.128 -j SNAT --to 1.2.3.4
iptables -t nat -A PREROUTING -d 1.2.3.4 -j DNAT --to 10.10.10.128

This worked to make 1.2.3.4 send to a machine behind the firewall that had 
10.10.10.128 for it's IP. 


Thanks

-- 
Daniel Fairchild
C I Host | danielf@cihost.com