Netgear CG3000DCR Comcast Gateway


Known Issues

  1. Comcast has confirmed the CG3000DCR causes the severe problems with VoIP below that's persisting even after several firmware updates, even with the latest version 1.34 (as of 5/2/14).
  2. Firmware bugs cause intermittent spikes in latency on the LAN, causing audio cutting in/out and faxes failing.  This occurs even if the Comcast bridges the gateway.
  3. SIP ALG is enabled by default and causes one-way audio & phone feature failures.  Only Comcast can disable it.
  4. Software firewall interferes with phone registration.



  1. Buy a Comcast DOCSIS 3.0 compatible modem to replace the Netgear modem.
    • The best choices are the Motorola SB6121 or Motorola SB6141 - you can buy both locally at Best Buy or online.
    • This will save you money because you won't have to pay ~$5-10/month to rent the Netgear modem.
  2. Buy a compatible router if you don't have one and set it up.
    • We cannot setup the new router for you, but your IT or the manufacturer of your new router can help you.  They will need to move settings from the old to the new router to ensure your computers and other devices on the network work properly.
  3. Call Comcast to: 
    1. Return the old Netgear modem
    2. For help setting up your new modem
    3. Bridging the new modem to your new router
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