[SOLVED] Return Traffic To Subnet Behind Secondary Gateway Routing Issue

[PFTim]

I've got a problem that seems to be related to the new changes to routing in 2.1

I am running 2.1.3.

In summery: reply packets to connections initiated from a subnet behind a secondary gateway are being routed to the default gateway rather then the secondary gateway

The network layout is as follows

I've added a PBR rule so that traffic from the "Example Server" is specifically allowed with the "VPN Device" set as the gateway.  This rule is above the default allow out * rule
After doing this the "Example Server" can ping the client workstation at 192.168.161.50.  So that is all well and good.

The issue is that if the "Client Workstation" initiates the a telnet connection the packets arrive on the Example server as expected (Via Wireshark).  But the return traffic is sent to the Primary Internet Gateway as proven by doing a packet capture on the "PF Sense".

The "PF Sense" has a route for 192.168.161.0/24 using the "VPN Device" gateway 172.30.0.86

What am I missing?

[PFTim]

While I don't understand it yet….I found a fix.

https://forum.pfsense.org/index.php?topic=75620.0

post #2 by CMB.  Ticking "Disable reply-to on WAN rules" solved the issue.

I've tried Googling reply-to route-to but not found anything concrete about how or what it is used for.  Is this s freeBSD thing or I am missing something core to networking here.

I hate not knowing why this works.

Someone enlighten me?