Network Address Translation (NAT)

Background Information on the NAT:

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There must be some sort of network address translation (NAT) when network traffic moves back and forth between an internal private IP address space (LAN) and a public IP address space (WAN).

One of the first steps in configuring any firewall or perimeter device is to ensure that you can connect from your internal network to the internet or WAN for DNS, HTTPS traffic, and other purposes. Because you don't want to expose all of your private IP addresses to the public internet, you'll need Source Network Address Translation (SNAT).

Once internal hosts have access to the internet or WAN, the next step is to expose something on the internal network to the internet, such as a DVR, CCTV, or web server. Because an internet device cannot connect directly to a device on a private network, traffic must be forwarded from the perimeter device to the internal device. This is known as port forwarding or DNAT (Destination Network Address Translation) (DNAT).

  • Static NAT
  • SNAT -Source NAT
  • DNAT -Destination NAT
  • Dynamic Port Address Translation - Port overload