linux – Assistance with Iptables Forwarding Rules

i have read over 40pages of tutorials and not able to figure it out. Please somebody help me with forwarding rules.

  • Router 192.168.6.1
  • PC 192.168.6.254
  • Raspberry PI-wlan0 192.168.6.64
  • Raspberry PI-eth0 192.168.0.1
  • Device1 on RPI-eth0 192.168.0.3

All default routes and pings working with same interfaces(PC can’t ping RPI-eth0 because different interface).
RPI can ofc ping on all interfaces where connected wlan and eth.
Device1 can ping RPI(same interface)

net.ipv4.ip_forward=1

I want from my PC able to connect to the device1 port 80 through RPI wlan0->eth0 and get reply back.
So the flow would be:

192.168.6.254 -> 192.168.6.64 -> 192.168.0.1 -> 192.168.0.3 or

192.168.6.254 -> 192.168.0.3
and back the reply.

I would prefer not to edit any settings on my mikrotik router(192.168.6.1) as there might be different environment and i would need to change all over again.

iptables
all policy accept.
no masquarade no post/pre routing enabled.
Waiting for the instruction.

Thank you!!!