How Static NAT Works?

Static NAT:

A static NAT is a one-to-one mapping between two addresses. It includes both a destination address translation in one direction and a source address translation in the other direction. The translation can occur in either direction (as discussed shortly in the Destination and Source NAT sections) but it is limited to translating only one address to another.

Here is an example:

A masquerade or MASQ rule is the most common type of SNAT. It makes it possible to hide all internal addresses from the outside world. It accomplishes this by converting multiple internal addresses to a single external address in a many-to-one relationship. The public IP address is used to replace all of the source addresses.

This option is used to translate the source IP address of a host of outgoing traffic. These are of the following two types:

Masquerade: Masquerade dynamically translates the IP address. If This option is selected, then whatever address is on that outgoing interface will be applied to all the outgoing packets.

SNAT: SNAT applies static IP address to the outgoing packets This option requires IP address of outgoing interface to be entered.