I'm planning a little network here and I'm not sure about one thing. Network structure is shown on the image below. ISP binds an IP to a MAC address, so if certain MAC is connected, it gets assigned certain IP and gets access to Internet. There is no need for Switch 1 and Switch 2 to be manageable.

  • For this setup shown below, does Primary switch has to be manageable one?
  • Am I correct in my understanding, that in this scenario, Primary switch would have to clone MAC address registered with ISP, then assign IPs to Router 1, Router 2 and Router 3 (for example,, and respectively) and rest of the elements in the network can get their IPs either from the router they're connected to or from the Primary switch?

enter image description here

  • Switches don't change MAC addresses. For best results, your primary switch should be a layer 3 switch or router. But ultimately, D-Link devices, don't have paid support from the manufacturer, which makes them off-topic on this forum. You can try asking on Server Fault.
    – Ron Trunk
    Apr 30, 2017 at 18:46
  • @RonTrunk D-link device was just an example. Besides, I think this kind of question is not exactly for Server Fault. So, you're saying, in my case another router would be the best (L3 switch seems like an overkill for my situation tbh) and it's not achievable with a regular switch? Apr 30, 2017 at 21:13
  • How many IP addresses does your ISP give you? With your design, you need at least 3.
    – Ron Trunk
    Apr 30, 2017 at 21:26
  • @RonTrunk Just 1, thus the need of 'front' component to be able to clone MAC address. Apr 30, 2017 at 21:29
  • In that case, you definitely need a router. It will need to perform NAT (Network Address Translation).
    – Ron Trunk
    Apr 30, 2017 at 21:39

1 Answer 1


You have the router and switch scenario backwards. You need a router to connect to your ISP. Routers route between networks, and you need that to route between your network and the ISP network. While layer-3 switches can route, they cannot do NAT, which you will need if you use private addressing on your network.

Where you have routers, you probably want layer-3 switches. Router interfaces are expensive compared to switch interfaces, and you rarely want to use a router interface for a single host. Layer-3 switches will allow you to have different networks behind each switch, and still have a high access interface density. It may also eliminate the need for the next level of switches.

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