Connecting Ion to Mirror Mode and IRFR via router

Question

So I was trying to connect nomad in mirror mode on a macbook to an Ion (just updated yesterday) while also having having the ion be accessible to IRFR on an iPad. According to my PM the previous way it was setup was that the board ran via Ethernet from Network Port 1 to the LAN port on an Apple router. The router also had the macbook connected via a LAN port. The WAN port on the router was run to a wall port that supposedly connects to the internet. However when I tried this setup neither the IRFR or the mirror mode worked. 
 
 I have been able to successfully get the mirror mode to work if I connect the macbook directly to network port 1 on the Ion, and I got the IRFR to work as well when I connected the ION directly to the WAN port on the router. I even tried running the macbook out of a LAN port while the ION was in the WAN and this didn't work either. As a compromise I tried running either the router or the macbook out of Network port 2, but it didn't work. Most likely that port isn't configured in the same way that network port 1 is. 
 
 Any help would be appreciated, as I am not the best at networks!

Wuz314159 · Accepted Answer

Check your devices for static IPs. 
Then see if there is a subnet in place that is preventing the devices from communicating with each other. 
 
If you don't understand those words, try this: www.youtube.com/watch

Mike A · Answer

The quick fix would be grab a $10 unmanaged hub/switch and plug the ion into it and the Mac and the wan port of the existing router. That way you will replicate the setup that you’ve proved worked in two separate setups. 
 
If you want to fix it without doing that you will need to configure the router probably turning off dhcp server on it and depending on how clever it is making sure there is no cross port protection stoping traffic between the ports. This is one case where more expensive is often worse !!