Openwrt for testing

I wanted to test a tap for performance with minimal equipment. I want to generate traffic between LAN2 & LAN3 and test the results from the tap on LAN4. I setup the following (see diagram).

  • Created namespace virtual ethernet on LAN2 and LAN3. LAN2 is able to ping LAN3 through the tap. (this works)
  • LAN4 & LAN5 are on the default vlan and br-lan network. no modifications.
  • LAN4 is setup with "tcpdump -i LAN4" to capture the ping traffic.
  • The pinging works fine, however it stops as soon as I plug net3 into LAN4. I get a message that says "received packet with its own address on LAN4". Which makes sense, so I set different MACs on LAN2, LAN3 and LAN4, br-lan. I no longer get the messages after the change, but the pings still stop when net3 and LAN4 are connected.

Is there a configuration in Openwrt that will allow me to do this?
What I have tried....

  1. Tried to set remove LAN4 from br-lan and moved to different VLAN and its own bridge. (didn't work)
  2. Instead of using LAN4, I tried using the WAN interface. (didn't work)