dhcp - Use a combination router/modem as a slave to another router

06
2014-04
  • Tyler DeWitt

    I've got a combination cable modem/router from my cable company. I've also got a Netgear N900 that I love. I'd like to use the advanced features of the N900 (partitioning, guest networks, print server). I think I have to chain the units together, but I'm guessing I need the N900 to act as the DHCP server in that setup (I'm assuming that the advanced features rely on DHCP).

    I can easily hook up my N900 as the slave device (disable DHCP, change IP), but I couldn't figure out a way to go the other way around, where my combo unit gets DHCP disabled and a static IP assigned to it.

    Is this possible with a combo unit, to have it act as a slave?

    It's a Cox combo unit (maybe a 'Netgear DOCSIS 3.0 11-N Router'?).

    • Answers
  • MariusMatutiae

    There is really no problem with this configuration. Draw a cable from a LAN-side port of your modem/router to the WAN-side port of your Netgear N900. Leave DHCP on, allow the Netgear to get an IP address on its WAn side by means of the modem/router DHCP. Make sure the two internal networks (that of the modem/router and that of the Netgear) are distinct, otherwise your Netgear will be puzzled when it gets a request to forward a packet to a given address, since it will not know whether the address is on the WAN or on the LAN side.

    You may pick, as the LAN side net of the Netgear, something unusual, like 192.168.211.0/24, which will come in handy if you want to set up a VPN, or if you need to connect to one.

    Lastly, make sure all of your devices go through the Netgear router, so they belong to the same subnet, and they are all visible to each other. Your Netgear router will be the only client of the modem/router.

    Turn everything off, then on, starting with the modem/router, then the Netgear router, then the other devices on your LAN. That's it.


    • Related Question

    wireless networking - How to configure DHCP for a wifi access point in front of a DSL router
  • Grumdrig

    What's the general procedure for adding a wifi access point to a DSL modem connection. That is, I've got

    DSL router -> Desktop computer

    and I want to get to

    DSL router -> Wireless router -> Desktop computer & Laptops via wifi

    If it matters, equipment is:

    • Wireless router: Netgear WGR614
    • DSL router: Speedstream 5100

    Right now I've got the DSL router with local IP 192.168.0.1/24, the wireless with 192.168.0.100, but I'm having trouble with DHCP. Which router is supposed to assign the addresses? If I give clients a static IP in the range all works - otherwise somebody grabs the remote IP and no one else can connect to the internet.

    Maybe I'm supposed to use the Netgear to replace the Speedstream entirely but I couldn't get that to work.

    Should the Netgear be on a different subnet entirely or something?


    • Related Answers
  • William Hilsum

    I regually set this sort of thing up. What you basically want to do is see if your wireless router supports standard "access point" mode. Failing this, try disabling NAT and DHCP which basically does the same thing.

    After you have done this, just plug one RJ45/ethernet cable in to your current router and then it should provide wireless access to the network.

    That being said, I would personally use the Netgear as your main router. Make sure you have copied ALL settings from all tabs such as Multiplexing Method, VCI, VPI along with all your account settings.

    If you cannot find this, try Googling your ISP's name and the router and see if anyone else has reported what settings you need. Lastly, failing this, ring up your IP and ask for the settings.

  • 8088

    I know this is old but the best solution is to put the DSL modem in bridge mode. This allows the router to get the external IP address and do its thing. Here's a guide on how to put your modem in bridge mode:

    1. In your web browser browse to »192.168.0.1 This address will be located on a yellow sticker on the bottom of your modem.

    2. The first screen will ask you for your Modem Access Code. This also will be located on the same yellow sticker.

    3. Select Advanced from the blue buttons on the left.

    4. Click the PPP locations button.

    5. The modem may ask your for the Modem Access Code again. If so type it in again and click continue.

    6. Select the radio button labeled, "Bridged Mode (PPPoE is not used)"

    7. Click Save Changes.

    8. A "PPP Location Warning" page will come up. Click "Change PPP Location."

    9. A "Restart Needed" page will come up. Click "Restart"

    10. Reboot your computer and router (if applicable.) You will now need some form of PPPoE software on your computer or a router that supports PPPoE. Be warned that even if you are using Enternet 300 or XP/OSX's built in PPPoE SBC tech support will not troubleshoot connectivity issues until you have put your modem back in PPPoE on board mode.

  • Roh

    Turn off DHCP on the wireless router, and give the wireless router a static IP address OUTSIDE the range of IP addresses that the Speedstream is handing out. Connect the two routers from LAN port to LAN port.