Is NAT can provide some kind of protection?

david raistrick drais at
Wed Jan 12 14:53:07 CST 2011

On Wed, 12 Jan 2011, Chris Adams wrote:

> Yes, they do.  NAT requires a stateful firewall.  Why is that so hard to
> understand?

Um.  No.  NAT requires stateful inspection (because NAT needs to maintain 
a state table), but does not require a stateful firewall.  You can (and 
many CPE appliances do/did) have no firewall, or stateless firewall in 
front of NAT.

All NAT does is give you an implied deny-all-inbound rule, but doesn't, in 
and of itself, prevent someone probing open (configured by you or the 
vendor) ports that are forwarded or on the device.   Or from having 
unfettered inside access of 1 internal IP if you NAT all external ports to 
an internal IP.

david raistrick
drais at   

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