Hello all, I recently purchased a CM1200 modem and R8500 router in order to upgrade to Gigablast by Cox. Currently testing setup and it works flawlessly as long as my pc is hardwired to the R8500. But when I connect the pc to one of the other ports on CM1200, the R8500 loses connectivity to the internet and the pc encounters slow internet speeds (20Mbps). I need pc and R8500 connected to CM1200 since router will be in another room in the future. Any help would be greatly appreciated. Thanks,Jay

Many cable ISP allow only one device only issue one IPv4 address to one MAC address - sometimes the cable modems require a restart before other sysems can access the netwrok again. So either a PC, or the router.

No internet on R8500 when pc connected to CM1200

6 Replies

schumaku
Guru
Jun 22, 2019
Many cable ISP allow only one device only issue one IPv4 address to one MAC address - sometimes the cable modems require a restart before other sysems can access the netwrok again. So either a PC, or the router.
- Jay924
  Tutor
  Jul 03, 2019
  Schumaku,
  I've tried your suggestion to no avail. Once both the R8500 and the pc are connected to the modem, the speed in my network drops and Wi-Fi connectivity issues arise. I know the R8500 is cloning the mac address of my pc and that is probably part of my problem. Should I use another device (laptop) that will not be hardwire to the modem? I do have another question, should the connection to the r8500 go into the port label as internet or one of the other ports when connecting the R8500 and pc off the CM1200?
  
  Thanks,
  Jay
  - antinode
    Guru
    Jul 03, 2019
    > [...] So either a PC, or the router.
    
    > [...] Once both the R8500 and the pc are connected to the modem, [...]
    
       Which part of "either" was unclear? A least one of us needs to read
    this stuff more carefully.
    
       Visit http://netgear.com/support , put in your (modem) model number,
    and look for Documentation. Get the User Manual. Read. Look for
    "Connect Your Cable Modem to a Computer", where it says:
    
          Note: Your cable modem comes with a plug that covers the LAN 2, 3,
          and 4 ports. You can remove the plug to connect a router that
          supports Ethernet port aggregation. For more information, see the
          cable modem's user manual.
    
       You have to admire the quality of documentation which tells you to
    read the manual which you are already reading.
    
       Where does it say that you can connect multiple devices to the
    modem's LAN Ethernet ports?
    
       Connect the modem LAN 1 port to the router WAN/Internet port.
    Connect other devices to the _router_. (Leave the unused ports on the
    modem unused.)
    
    > [...] I need pc and R8500 connected to CM1200 since router will be in
    > another room in the future. [...]
    
       That's too bad, because it won't work that way, as you've
    demonstrated. Run more cable?

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No internet on R8500 when pc connected to CM1200