Wireless router used as access point: WAN port

Question

I'm a bit confused. I apologise. I have a new ADSL router and I would like to use my old one as access point. Therefore I disabled DHCP server and assigned it a static IP on the same subnet. I have connected a patch from an Ethernet interface from router to the oldest. But... I have to connect in any of the Ethernet interface or to the WAN port? What is the difference?

Solution

You need to connect the Ethernet cable from a LAN port on your new ADSL router/modem to a LAN port on your old "access point."

If you connected the cable to the old router's WAN port, you'd encounter two problems given your current configuration:

First, your former router, now access point's WAN port will not allow unsolicited traffic to flow into it. Therefore if you connected your new router to this port, any device connected to your new router wouldn't be able to communicate to the (wireless) clients that connect to your old router.

Second, since you assigned an IP address to your old router (to it's LAN interface, I assume) that's valid on your new router's LAN network, devices that connect to your old router wouldn't be able to talk to your new router's network. This is because the old router would end up with identical IP subnetwork configurations on its WAN and LAN interfaces. For example, both interfaces would have a 192.168.x.x/24 IP address. This would make it impossible for the router to know where to send traffic since it's supposed to move traffic between different IP subnetworks.

Comments

[Xen2050]

I just read an article about that, found from searching something like "use old router as switch" since that sounds like what you want. Connecting to your old router's lan port should work for you, I think you'd need custom firmware (dd-wrt/openwrt/tomato) to make it super easy to use the wan port. Otherwise the wan port would probably create a separate subnet (not a super answer, so just a comment, but follow a web search to read more)

[Tim_Stewart]

superuser.com/questions/1295426/…

[robyg72]

Thank you very much! I was not able to find this article :-)