10

I would like to use a second router to set up a second network on my home network.

The first router is plugged into our cable modem. I have that plugged via Ethernet from one of the LAN ports on router 1 to on of the LAN ports on router 2. Is this correct or should it be plugged into the WAN port?

  • Router 1’s IP is 192.168.1.1.
  • I set Router 2 to be 192.168.1.2.

Right now they’re both on the same subnet. How can I get them so they’re on separate networks?

Router 2 uses DD-WRT and it doesn't allow me to use DHCP to set them on something other than 192.168.1.x while it has a 192.168.1.x address.

Any help would be appreciated.

2
  • You have to use VLAN's to define a different subnet with DD-WRT. The tricky part is not all consumer router chips have VLAN capability. See if your router supports VLAN here: dd-wrt.com/wiki/index.php/VLAN_Support
    – Larssend
    Jul 11, 2015 at 22:59
  • If your router doesn't have VLAN capability, you'll have to change your topology; connect Router B's WAN interface to Router A's LAN interface. Set Router B's WAN interface IP to be in the same subnet as Router A's LAN. Router B's LAN IP will have to be in a different subnet, of course. To facilitate communication between both subnets, you may have to configure DMZ or port-forwarding.
    – Larssend
    Jul 11, 2015 at 23:13

2 Answers 2

12

I understand this question is a few years old, but it still pops as first result on google searches, so here is the most direct route for what the asker was trying to achieve.

Modem -> WAN on Router A

LAN on Router A -> WAN on Router B.

Router A configured with a DHCP pool of 192.168.1.1/24

Router B configured with WAN port at an IP in the 192.168.1.x range (or just set to receive dynamically), and a DHCP pool on the LAN side of 192.168.2.1/24.

5
  • 2
    Note that this is what this question asks for, but not what most people wants. The second network will have double NAT and will not be able to access resources on the first network. Most people want one big LAN. Apr 21, 2017 at 1:14
  • @DavidSchwartz What are the advantages/disadvantages of having two separate networks vs having one large one? Would they both provide roughly the same range and speeds? Dec 19, 2018 at 20:07
  • It's not so much whether you have one network or two, it's the relationship between the two networks. This makes one LAN appear to a WAN to the other LAN but not vice versa. Dec 19, 2018 at 20:08
  • So two networks will be separate, nothing from one network could access hosts from other network but they still both networks will have Internet access? is that correct?
    – kodlan
    Jan 21, 2022 at 13:54
  • A use case is when you're renting a room. you can connect the second router to the main router and setup your own network. You can setup smart devices with your own network and the other network won't have access to those devices.
    – chrony
    Aug 11, 2022 at 3:06
1

When a packet from router 1's client, let’s say from 192.168.1.5/24 wants to send a packet to a client on router 2, let’s say 192.168.2.5/24 it simply cannot.

Routers that we use at home would send a packet that is addressed to a client in different subnet to the gateway and in this case it would be 192.168.1.1.

Little does router 1 know the presence of 192.168.2.0/24 unless your router supports routing; either static or some routing algorithm.

If it does then the routing table in router 1 should have an entry for 192.168.2.0/24 and the port that can be used to reach it.

1
  • I would imagine that is the point of the OP when he says separate network. But thank you the explanation of why the 2 networks would not be able to communicate unless special settings/considerations are made. Jul 26, 2023 at 13:55

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .