My goal is to be able to have a client connected using a wired Ethernet connection to a switch and have the choice between two networks using the one cable.

The basic setup I have goes like this:

wide demo pic

At the moment the Tp-Link router is connected to the switch by it's WAN port, but I can change the cables around as per anyone's suggestion.

The Tp-Link router is on a separate subnet. My idea is to have a server and a few clients on the Tp-Link subnet so they can all talk to each other and for that network to be separate from my main network (ATT). This way the devices on the Tp-Link subnet can not "see" the devices on my main network. I then want to connect my laptop to one cable so that it can function on my main network, but then I can toggle to the Tp-Link subnet to manage the server on it.


I plug my laptop into a cable that connects to my switch. I can click on the network icon and see 2 separate wired networks (as though my laptop had more than one Ethernet port, but only one is connected). I can then choose which network I send data through (toggle between the two networks). This would be analogous to switching between WiFi networks detected by a single WiFi adapter.

How might I achieve this?

If there is any other information I can add please comment and let me know.

  • 1
    HI Nate - can you edit and clarify? Yes, you can have multiple routers in a network, this is common. But it isn't clear from the description above what it is you want to achieve - what choice is being made. What is meant by "see"? Tell us what your goal is. – Paul Aug 12 '18 at 23:25
  • It can be done, but it’s complicated and takes several parts the first of which is separate VLANs running on the network. Then you’ll either be able to accomplish which PC gets which network by MAC addressed based DHCP reservations that can be assigned to different networks, or some type of captive portal (like hotels use) where the user must open a browsers and supply some piece or info or possibly credentials to access the network. This is an advanced level networking project, it’s not for beginners and most intermediate level, this would be a challenge at pro level, but it can be done. – Tyson Aug 13 '18 at 0:22
  • then choose which network I send data through...Please clarify this part. You're only using a single cable to connect to the network, so what do you mean by choose the network I send data through? – I say Reinstate Monica Aug 13 '18 at 0:38
  • @TwistyImpersonator I could toggle between the two networks. This would be analogous to switching between WiFi networks detected by a single WiFi adapter. – Nate Goldsborough Aug 13 '18 at 0:55
  • @NateGoldsborough You need to tell us more about what you're trying to accomplish. While it may seem like what you're asking is like switching between networks, the fact you're using the same network cable for both means in some aspects of network function they'll still behave like a single network. Without knowing your goals it's foolish to propose a strategy given these caveats. – I say Reinstate Monica Aug 13 '18 at 1:06

Your PC's network definition will be comprised its designated IP, network mask and gateway.

The routers that you connect to the gateway should at least have a different IP each - they may be using the same network mask. If they both distribute DHCP addresses, the DHCP address range should not overlap.

If you use DHCP, then the gateway you get assigned will depend on the DHCP server (router) that assigned your address. If you use manual configuration, you can select your gateway according to your liking and you will use the router that corresponds to this gateway IP which is the IP of the router.

There are cleverer solutions involving a firewall like pfsense that is capable of managing this, and you can also use commercial solutions that will aggregate several internet connections. That is: you connect to a local device that will distribute the packets accross the available internet connections and they are aggregated in the datacenter. This increases your effective bandwidth and also protects you from a failure in one of your internet connections. In that particular case, all routers are on the same switch but all their DHCP servers are disabled. The local device is distributing the DHCP addresses and acts as a gateway for the local network. That local device then distributes, encrypts and compresses the data across the available routers/connexions.

OVH has released this as open source https://github.com/ovh/overthebox .

| improve this answer | |
  • But how might I have both connections visible using one Ethernet cable. I know you can do it with a wired and wireless connection together, but how would it work with only one cable? – Nate Goldsborough Aug 13 '18 at 0:18
  • @NateGoldsborough You are going to need to add more detail to the question to get sensible answers. There isn't a "both connections" in the above diagram. There is a single ISP connection, with multiple routers to get there. – Paul Aug 13 '18 at 1:10
  • @Paul I edited my post with more info. Hope it helps. – Nate Goldsborough Aug 13 '18 at 1:39
  • @NateGoldsborough: You can either use a switch to which you connect your routers and your computer (3 cables), or your routers should act as switches too and you can interconnect the LAN side with one cable and then connect your PC to another input. No guarantee: but you can probably connect through Wifi also. So: put both routers on a different address in the same subnet, interconnect them with a cable and connect your PC to that network either through WiFi or cable. Of course if you use WiFi to connect, it is likely that the DCHP of the corresponding router reacts first. – le_top Aug 13 '18 at 11:24
  • @Paul, Nate: The added diagram changes things a bit. If you want ot connect to your server from your main network, you can also set it up as a DMZ on your TPLink router (or definer routing rules) so that you can connect to it from the TpLink WAN network (which is the local network on your other router) without switching networks on your PC. Or setup a VPN to your server through the TPLink. – le_top Aug 13 '18 at 11:30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.