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I want to connect two routers to a switch which will then be connected to a modem. Now as far as I know a switch does not do network translation and this won't work with one IP address. So I bought two addresses at my ISP.

Attached is a simple schematic that explains what I want to do.


Is there any additional configuration needed on either of the routers (Linksys WRT54GL) to make this work or will it "Just Work"?

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What exactly do you mean by "Just Work"? How are you going to use those two routers, and what functions are we validating in our answer? – Mike Pennington May 29 '12 at 10:13
By "Just Work" I mean that clients will be able to connect to either router with no problems. The routers do not need to be aware of each other, clients connecting to one router do not need to know the other even exists. – vanneto May 29 '12 at 10:19
You don't need 2 public addresses to make this work. Just route private addresses and nat once on the modem. – Matt H May 29 '12 at 10:22
The question that comes to mind is what kind of Routers, how will they be configured and what purpose will they serve to clients. A typically, consumer Wireless router creates its own Subnet so it can help isolate both of them. If you are keen on dual ISP, then instead of 2 routers downstream from Switch, you'd want to look into Dual WAN Router upstream from Switch. Its not clear what equipment you are using and what you are trying to achieve. – Alex S Aug 11 '15 at 6:32
This will create two LANs, and clients of router 1 won't be able to talk to router 2. What are you trying to achieve here? Why are you using two routers? – David Schwartz Sep 15 '15 at 2:50

This should just work. But i would make sure router 1 and router 2 client sides are on different subnets.

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+1 but consider providing an example of different subnets – Jeremy W May 30 '12 at 3:36

EDIT: Apparently I was wrong, you can get two different IP addresses while using one Modem to connect. When I tried doing it, it didn't work, so maybe it depends on the ISP or the modem, or maybe I didn't configure it properly...

You can use the Routers to manage the clients in two subnets and configure the routers separately.

For example, you can use one router to configure a Wireless network and the other to configure a LAN network.

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not true. Business class cable or DSL will assign a small range of public IPs if asked (and paid for). – Jeremy W May 30 '12 at 3:33
AFAIK Using a regular modem will only connect one user account with only one IP address assigned to it. – Shahar May 30 '12 at 5:37
@shahar I used to have about the same setup with my cable ISP. – Sibster May 30 '12 at 6:06

it's just work... because switch is device to share connection. You must setting routing table and NAT for routers. in the computer client, you must fill gateway with IP address of router...

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This question is really an old question, Hope you have already solved it, but I have some ideas to share with you.

You are talking about 2 physically separate routers connecting to PoE switch.

Yes, that is possible. You create 2 vlans on the switch. Lets say you create vlan 100 and 200, then add port,lets say 10 to vlan 100 and port 20 to vlan 200. Now you have one PC connected to port 10 and one PC connected to port 20. And don't forget to assign the IP address.

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