NAT mapping/inbound port forwarding question


#1

Hi all. I have a question regarding NAT mapping/inbound port forwarding.

Referring to this document: http://www.peplink.com/knowledgebase/having-multiple-subnets-behind-a-router-on-the-lan/

If we can perform NAT mapping from WAN2 IP directly to a private subnet behind a Layer 3 device via static route, why do we even need to perform NAT to WAN1 IP?

Eg:

  • 192.168.1.1 > 2.2.2.2 via static route to Layer 3 device
  • 192.168.1.1 > 1.1.1.1, then 1.1.1.1 > 2.2.2.2

Since both the above achieve the same result, is there any particular reason that we would prefer one over the other?


#2

A LAN static route tells the Balance about an internal network. An inbound NAT mapping creates a path from WAN to LAN devices. The outbound NAT map can be used to go out a WAN using additional public IPs.


#3

Hi Ron, thanks for your reply. I guess I might need to rephrase my wordings.

NAT Mapping:

WAN2 IP > LAN IP via static route to a Layer 3 device in between(under WAN1 subnet)

WAN2 IP > WAN1 IP > LAN IP

Both will achieve the same result of inbound NAT mapping so external users can reach an internal server via WAN2 IP, and also create inbound load balance between both WANs. So my question is: is there any point in choosing one method over the other?

I’m using this article as a reference.


#4

Can you share the network diagram with IP address for better understanding? Are you using Drop-in mode?