Re: IPTables and different types of NAT

["Pedro Gonçalves" <pedro.pandre@gmail.com>]

Pascal Hambourg wrote:
>> "Full Cone Nat" could easily be implemented with inbound redirection 
>> to the internal system.
>
> "Full cone NAT" can be implemented with 1-to-1 bidirectional NAT using 
> SNAT+DNAT or NETMAP.
>
>> "Port Restricted Cone NAT" is nothing more than "Restricted Cone NAT" 
>> with port filtering.  This is what is usually done if you have a 
>> server behind a NATing router / firewall.  In this case, you only 
>> port forward the ports that you need.
>
> No. Please read more carefully the definitions of "restricted cone 
> NAT" and "port restricted cone NAT". Neither can be implemented with 
> iptables because they do not fit in the per-connection model.
>
>> I'm not sure if there is inherent support for "Symmetric NAT" or not. 
>
> "Symmetric NAT" works on a per-connection basis and is the NAT form 
> that is the easiest to implement with iptables using SNAT or MASQUERADE.

This is the main reason why I am asking: some people say it is possible 
to implement all this types of NAT, some say it's not.

Pascal, can you tell me where can I find information regarding the 
implementation of "Full Cone NAT" and "Symmetric NAT" using IPTables?
All I can find is discussions about whether it is possible or not to 
implement this.

Thanks a lot
Pedro