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Forum Discussion
Schema of a Smart Home: One IP => Multiple MACs
I use an XR700 router with a EX8000 extender. They were expensive and I hope that they would provide my household a few more years of service. I want to use TP-Link Smart Plugs (Kasa brand) becau...
Definitive illegal to have one IP address with multiple MAC. The mess is predictable once both MAC addresses appear on the same L2 network. All alerts must ring in case the same IP address appears with different MAC addresses!
The reason why Netgear (and other makers of legacy extenders) implementing what is designated as MAC translation is key of that specific design, because the same MAC address should never appear on what are different interfaces. It was not chosen to make our life hard, it was selected to keep things easier with the implementation. Technically, these extenders are not bridges, but much more streamlined L2 NAT routers - and behave completely independent to the IP addresses.
Those routers resp. their DHCP servers which allow to define multiple MAC addresses on the IP-MAC work on the (wrong!) expectation the same device has always the same IP address - completely misleading, and prone to errors and mishaps.
The obvious reason why the MAC address must be unique is in the ARP protocol. So everything just to get some kind of *fixed" IP addresses? In the times of Bonjour, WS-Discovery, and multicast DNS a complete obsolete approach from the 1970ties when ARPANET (based on 1986 ideas) and IPv4 was designed.
schumaku wrote:Definitive illegal to have one IP address with multiple MAC. The mess is predictable once both MAC addresses appear on the same L2 network. All alerts must ring in case the same IP address appears with different MAC addresses!
One Mac for each IP was a great idea, but wasn't that law broken with the advent of Virtual MAC Addressing?
Of course this is already broken. My router already shows (see my second screen-shot) a device with one IP and two MAC addresses. We are indeed already living in the mess caused by the reality of two MACs per IP.
What does an industry leader, NETGEAR, offer as a solution to this problem that they co-invented?
That mess, specifically, is expressed as a device that can no longer be statically-addressed by MAC or IP.
Do you really suggest clients look for proprietary solutions to get a handle on a device, like a Bonjour name or an Alexa registry? Do I really want to hard code: "Alexa, Turn of the pump" ?!?
Many people have thrown up their hands and simply shut down the Netgear DHCP server because it provides no reliable device tracking. When you bring in secondary devices running DHCP and DNS, that's a whole new level of messiness, complication and unreliability. I think there is a better solution to be offered on the router and I hope someone is smart enough to invent it and implement it on hardware that I've already invested in.