Setting up repeater using a lan port

Question

I have two routers at home, one Cisco and One DLink. The Cisco Router is the main router and the DLink router is set up a repeater.

The connection between the two routers is made using a wired connection, from LAN port of main router to Lan port of the secondary router.

Currently, the main router handles everything(DHCP and internet connection). The secondary router is just set-up as a repeater with no DHCP.

Everything is working perfectly fine. But I was wondering why I need to connect the LAN port of the main router to the LAN port of the secondary router.

But if I try to connect the LAN port of the main router to the WAN port of the secondary router which is set-up as repeater, the connection does not work. Why is that so?

Answer 1

Attaching it to the WAN port, would mean that traffic hits the firewall of the second router, and splits it into another subnet as well.

While most of the functionality can be turned off on more expensive enterprise routing devices(which turns the WAN port into just another LAN port), it can't(generally though firmware hacks do exist) easily be done on cheaper devices such as this.

You could setup the 2nd router to connect to the first on the WAN port, using DHCP. It'd get a IP from the cisco router, and then have it's own subnet, fire walled off and possibly behind NAT as well. However, this just ends up making your network far more complicated than it needs to be.