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tanviper's avatar
tanviper
Aspirant
Nov 24, 2019

CM1200 not working with wireless routers

I went from cox's 150 internet service to their gigablast service yesterday. I knew I was going to need a new modem as my old one wasn't 3.1. I purchased the Netgear CM1200 and got it setup. My computer--which it plugged directly into it--gets online. My linksys AC8500 wireless router refuses to work with this new modem, and I've tried every port on the back of the CM1200 modem, verified the modem is plugged into the yellow "internet" port on the back of the router and even tried different cat 5e cables. So, I thought, maybe it's this router, and went and bought a new linksys AC2200 router to swap it out with. It's doing the same thing. I can't get either of these 2 linksys wireless routers to work. I've reset back to factory settings both routers and even the CM1200 while trying to troubleshoot this issue. I can connect directly into the wireless routers if I plug my computer into either one, but they won't PING when connected to the CM1200. All my 4k Firesticks, blink cameras, garage door, NEST, laptops, etc need wireless, and right now I'm plum out of ideas. Can anyone help? 

11 Replies

  • plemans's avatar
    plemans
    Guru - Experienced User

    tanviper wrote:

    I went from cox's 150 internet service to their gigablast service yesterday. I knew I was going to need a new modem as my old one wasn't 3.1. I purchased the Netgear CM1200 and got it setup. My computer--which it plugged directly into it--gets online. My linksys AC8500 wireless router refuses to work with this new modem, and I've tried every port on the back of the CM1200 modem, verified the modem is plugged into the yellow "internet" port on the back of the router and even tried different cat 5e cables. So, I thought, maybe it's this router, and went and bought a new linksys AC2200 router to swap it out with. It's doing the same thing. I can't get either of these 2 linksys wireless routers to work. I've reset back to factory settings both routers and even the CM1200 while trying to troubleshoot this issue. I can connect directly into the wireless routers if I plug my computer into either one, but they won't PING when connected to the CM1200. All my 4k Firesticks, blink cameras, garage door, NEST, laptops, etc need wireless, and right now I'm plum out of ideas. Can anyone help? 


    That's your problem right there. Even though the CM1200 has 4 ports, your isp only supplies a single ip address. And your computer is using it. If you're on a business setup, the isp can supply more but most aren't as its more expensive. Port 1 is used for connections to router. You can use port 1 & 2 if your router supports wan port aggregation but I don't think your linksys does. 

    So unhook your computer from the modem, reboot it, and hook the router up to it.

    • tanviper's avatar
      tanviper
      Aspirant

      ". Even though the CM1200 has 4 ports, your isp only supplies a single ip address"

       

      I did as you suggested, and it's working now. There's now a new issue. My connected speed dropped by 2/3. I was getting 900 megs testing out to fast.com when my computer was plugged into the CM1200, now that it's going through the AC3500,i'm getting 300. Is there something else I need to look at?

       

      Correct me if I'm wrong (my network know-how is limited here)

       

      1) ISP assigns IP address to you

      2) I THOUGHT it was assigned to the cable modem since you have to give the ISP (Cox) the serial number, model #, etc.. off the modem.

      3) CM1200 has 4 ports on the back, i THOUGHT the modem assigned an interanl IP to those ports so you can have 4 devices directly connected to your CM1200 without them "grabbing" the ISP assigned IP adddress.

      4) What good are the extra 3 ports if I can't plug my computer into them?

      5) My CURRENT set up is CM1200 with only 1 thing plugged into it (the AC3500) and then everything plugged into it.

      6) I'm also using a smaller DGS 105 switch (it's a unmanaged, 5 port Gigabit switch from linksys)  for a few smaller things since my AC3500 doesn't have enough ports in the back (it's using one of the ports on the AC3500 and a few items are plugged into the DGS 105.

      7) computer is plugged into the AC3500, not the DSG 105 (just want to be clear)

      • plemans's avatar
        plemans
        Guru - Experienced User

        tanviper wrote:

        ". Even though the CM1200 has 4 ports, your isp only supplies a single ip address"

         

        I did as you suggested, and it's working now. There's now a new issue. My connected speed dropped by 2/3. I was getting 900 megs testing out to fast.com before switch all of this, now i'm getting 300. Is there something else I need to look at?----Your router. If you were getting full speeds from the modem with it directly connection and then speeds drop when you go modem----router----pc. The router is what's limiting it. Not sure about the linksys settings but I'd check with linksys as to why their device is slowing things down. Sometimes is qos, parental controls, etc thats slowing speeds. 

         

        Correct me if I'm wrong (my network know-how is limited here)

         

        1) ISP assigns IP address to you----Most isp's only assign a single ip address. for consumer connections.

        2) i THOUGHT it was assigned to the cable modem since you have to get ISP serial number, model, etc..

        3) CM1200 has 4 ports on the back, i THOUGHT the modem assigned an interanl IP to those ports so you can have 4 devices directly connected to your CM1200 without them "grabbing" the ISP assigned IP adddress---Sadly, no it doesn't work this way. 

        4) What good are the extra 3 ports if I can't plug my computer into them?----not a whole lot if you're ISP doesn't assign multiple IP addresses per account or if you don't have a router that has wan link aggregation. I  usually recommend the cm1000 or cm1200 for most home users. they're the same basic modem internally. 

        5) My CURRENT set up is CM1200 with only 1 thing plugged into it (the AC3500) and then everything plugged into it.---that's how it should be. 

        6) I'm also using a smaller DGS 105 switch for a few smaller things since my AC3500 doesn't have enough ports in the back (it's using one of the ports on the AC3500 and a few items are plugged into the DGS 105.----correct. It should go modem----router----switch/devices.