3.3.2 nat

The nat table handles packets that initiates a new connection. It is used to facilitate NAT (network address translation). It is not used for network filtering/restriction. It has three chains:

• PREROUTING: this chain applies to incoming packets.
• POSTROUTING: this chain applies to outgoing packets that are not generated by the local host.
• OUTPUT: this chain applies to outgoing packets that are generated from the local host.

Note that the nat table is specifically there for NAT (network address translation) This concept should be discussed in another module dedicated to NAT.