Known Issues

  1. SIP ALG is enabled by default and cannot be disabled.
  2. DNS servers need to be configured to a set of efficient DNS servers in order to prevent issues with registration on Polycom phones.


  1. Log in to the router. Default credentials are
    • Username: cusadmin
    • Password: password
  2. Change the DHCP DNS servers (Polycom only)
    • Click on: Basic > LAN Setup > WAN Info > DNS Server
    • Enter the following:
      • Primary DNS Server:
      • Secondary DNS Server:
      • Click Apply to Save
  3. Reboot the router, phones and computers on the network.
  4. Call Intermedia Technical Support and ask a representative log into one of the Polycom phones after it reboots to check the very end of the phone's app log.
    • They will need to see if the log shows the phone's Primary DNS server as or not.
  5. Contact your ISP and inquire about the possibility of disabling SIP ALG.
  6. If SIP ALG cannot be disabled:
    1. Buy a Recommended Router if you do not have one already.
      • Our list of recommended devices can be found in this article.
      • Intermedia cannot set up 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.
    2. Call your ISP to assist with bridging the CGN3 modem to your new router, or to replace your current CGN 3 modem with a different gateway.