A recent firmware upgrade has allowed changes to be made to resolve the known issues. However, it depends on the model.

Known Issues:

  1. DHCP Auto-IP-Reservation is on by default which can cause "Network is down" or "DHCP Failed" errors on Polycom phones.
  2. SIP ALG is enabled by default. It can be disabled, depending on the model of the device
  3. We have tested and confirmed on several cases that the software firewall blocks phone registration if enabled because the stock firewall rules only allow SIP signaling through port 5060.
    • The software firewall is actually disabled by default because it can cause phone and other problems.
    • The gateway doesn't allow changing the SIP firewall rule port to 6060 or 6061 for Secure SIP, which Intermedia phones use.  Custom rules cannot be created as well so the software firewall needs to be disabled.
      • This does not mean your network is left unprotected.  Your network is still protected by the NAT firewall.  Disabling the firewall above just disables the stock firewall rules that block phone registration.
      • If you are concerned about security, then we strongly recommend that you purchase a firewall that will allow you to create custom firewall rules, which will give you far greater security than this ISP-provided device.  Our Recommended Routers page will provide you with a list of devices that we have found easiest to setup for VoIP/FoIP Services, depending on your needs and business size.

Temporary Resolution:

  1. Log into the router.
  2. Go to Advanced Setup > Security on the left-hand side of the page > Firewall Settings > Do the following:
    1. Stealth Mode -> Disable
      • This step is optional, but it's needed to allow your gateway to respond to our Call Quality Monitoring Server. 
      • This gateway doesn't allow creating a custom rule that will only respond to our server.  It instead bundles the 'WAN Ping response' setting that we need into what the gateway calls 'Stealth Mode'.
      • If you are concerned about security, see the Known Issues section above.
    2. Security Level > Set it to Off.
      • This is the default setting.
    3. Click on the DHCP Reservation> Disable Auto DHCP Reservation> Apply.
      • Older firmware versions may not have this option.
    4. Click on SIP ALG> Uncheck SIP ALG> Apply.
  3. Go to LAN Settings > DHCP Settings > Do the following:
    1. This step is only needed if you have or plan to purchase Polycom phones:
      1. These changes will take your computers, phones, and all other devices online for 10 minutes or much longer if an unexpected problem arises.
      2. Make sure to only make the changes below when you can afford to take your network offline.
      3. Go to Advanced Setup > WAN Settings
      4. Set the DNS Values > Select Static > Enter the following:
        • DNS Server 1: "".
        • DNS Server 2: "".
        • Click Apply to save changes.
      5. Reboot all Polycoms phones. 
      6. Check each computer and other network devices to verify they can still browse the internet.  If any cannot, reboot them. 
        • Some Windows computers may require running the following command from Command Prompt to restore the ability to load many websites:
          • "ipconfig /flushdns".

Permanent Resolution:

If any of the above options are not present then purchase a recommended router:

  1. Purchase a Recommended Router if you do not have one already.
    • Intermedia 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.
  2. Call CenturyLink to bridge your internet gateway to your new router.

Additional Resources:

  1. Recommended Routers.
  2. Recommended Switches.
  3. Recommended LAN Configurations.
  4. Network Ports and Protocols for HPBX phones.