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user_75b8o8
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Tuesday, July 22nd, 2025

Connecting two routers for two separate networks on one modem

I would like to have two routers connected to one modem. The goal is to have a separate "home" network and "work" network. The reason is that we work from home and my partner has a device for work that does not play well with the current home set up running through pihole. My initial understanding was that I could just plug both routers into ports on the modem and set them up separately. The second router would live in the office away from the home router to minimize interference. When I tried it, the modem could connect and auto detect IP type on router set up, but would not populate IP and give internet. 

Modem is an Arris from Xfinity with 4 ports in the back.

Router 1 is tplink archer a7 with ddwrt.

Router 2 is tplink archer a7 with tplink firmware.

Is there a step I need to take to set up 2 networks like this? Would it help to flash ddwrt on the second router?

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XfinityAirelle

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10 hours ago

Thanks for reaching out — we get wanting to keep your home and work networks separate, especially when certain devices need a more straightforward connection.

 

Unfortunately, Xfinity internet service plans only provide one public IP address. That means if you plug two routers directly into the modem (even if it has multiple ports), only one of them will get internet access, since the modem can’t assign two separate IPs by default.

 

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user_75b8o8

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@XfinityAirelle​ Okay, that makes sense. Would I, then, be able to chain the routers? Have the basic "work" network directly connected to the modem, and then the second "home" router with my home services connected to the first router? Would that still keep them separate so anything connecting to the main network would not interact with services on the second?

Thank you

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9 hours ago

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XfinityAirelle

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That’s a great follow-up — and yes, you can definitely set things up that way using a cascading router setup, also known as router chaining. Here's how it would work in your case:

 

You’d connect the "work" router directly to the modem, so that becomes your main network — ideal for keeping it clean and simple, especially if you’re avoiding pihole or custom setups for work devices.

 

Then, you’d plug your "home" router into one of the LAN ports of the work router, but make sure the home router is set to operate in router (not access point) mode, with its own DHCP enabled. That way, it creates a separate subnet, isolating your home devices and services from the work network. Devices on the work router won’t see or interact with devices/services on the home network, and vice versa — keeping things nice and separated.

 

(edited)

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9 hours ago

user_75b8o8

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Thank you for the explanation! I appreciate the assistance!

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5 hours ago

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XfinityDemitrius

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You're most welcome! If using the main router functionality of the modem, if your devices have Access Point (AP) mode, that would help as well since it would have its own WiFi SSID and still be assigning devices and router functionality from the modem still @user_75b8o8.

(edited)

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

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5 hours ago

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EG

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8 hours ago

@user_75b8o8  

Be advised that if you hang a router off of another router, and they both are doing DHCP, it will result in an undesirable "double NAT" condition on your second router / network. 
 
Google "double NAT" for info about its potential pitfalls. It may break some applications.

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user_75b8o8

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Thank you for this warning, I will look up "double NAT" and its consequences!

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5 hours ago

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