Stuck at setting up static route

[sunny]

I am trying to setup my opnsense router, as the setup is a bit complicated, I have draw a graph to have better understand about the situation.

Router:
WAN: 10.10.10.23
WAN2: 172.16.1.3
LAN: 192.168.1.1/24

My Computer: 192.168.1.100

What I would to access 100.100.0.14 computer through my router with the IP 172.16.1.3. However there is some problem with I try to it. Below I have illustrate what settings I have make to the default installation of opnsense.

1. Created a Gateway for WAN2
2. Create a route for 100.100.0.0/16 through that gateway
3. NAT-Outbound: Automatic outbound NAT rule generation

Below are the settings for Firewall

1. Pass all LAN incoming connection
2. Pass all WAN2 outgoing connection through the gateway as said above

During the testing phase, I am able to access 100.100.0.14 service when I SSH to my router and perform the request. However all LAN computers wasn't able to do so.
In addition, I found that when I request through LAN computer, there is two TCP request initiated, one from 192.168.1.100 (LAN PC) and one from the 172.16.1.3 (The router IP). Is it a bug?

[sunny]

Wireshark logs

[dseven]

Does "Others router" have a route to 192.168.x.x pointing back to "My router" (172.16.1.3)?

[dseven]

You may also need to configure your WAN interfaces to not "Block [private/bogon] networks"

[sunny]

Does "Others router" have a route to 192.168.x.x pointing back to "My router" (172.16.1.3)?

I don't have access / control over it. So I couldn't

[sunny]

You may also need to configure your WAN interfaces to not "Block [private/bogon] networks"

I have disabled those options, however it still doesn't work

[dseven]

Then I think you'll have to add outbound NAT for your "WAN2" interface. Personally I'd switch to Manual mode and explicitly add the NAT rules that I want, but you could probably use hybrid mode and just add a new rule for your WAN2 interface.

[sunny]

I have added the NAT outbound rules to change the IP address, however it still doesn't work. It seems that there isn't any response coming back from the server. Or after the server response the router wasn't able to change back the IP address and return the packet back to LAN.

EDIT: In addition, there seems to be a bug in opnsense, where after I add a manual NAT Outbound rule and enable logging. In the live view the log description will be empty even though I have type the description in the rule.