Network Address Translation


Source NAT
Used for routing a private network onto the world though a limited number of public IPs

iptables -t nat -A POSTROUTING -o eth0 \ 
        -j SNAT --to-source 1.2.3.1-1.2.3.14

Masquerade
Used for routing a private network over a dynamically allocated public IP
Connections are terminated if the interface drops

iptables -t nat -A POSTROUTING -o ppp0 \ 
        -j MASQUERADE