Recommendation Information

  1. Routers running DD-WRT have no SIP ALG on Register or Invite messages.

Known Issues

  1. The compatibility of routers running the DD-WRT firmware depends on if it is officially supported by the DD-WRT community.
  2. DNS server addresses need to be changed to set of efficient DNS servers, like Google's DNS or another DNS, to prevent intermittent registration failures on Polycom phones.
  3. DNS Masquerade should be disabled to avoid issues with name resolution on Polycom phones.
  4. WAN ping response to our Call Quality Monitoring and Troubleshooting Server, 64.28.122.100, needs to be enabled.

Temporary Resolution

  1. Log in to the router.
  2. Go to Administration -> Management and change the following:
    • UDP timeout (in seconds) to 300
  3. Go to Security > Firewall and change the following:
    • SPI Firewall: Enable.
    • Additional Filters:
      • Filter Proxy: Leave as is.
        • The default is Unchecked.
      • Filter Cookies: Unchecked.
        • This is needed to access Intermedia websites.
      • Filter Java Applets: Unchecked.
        • This is needed to run Intermedia troubleshooting tools.
      • Filter ActiveX: Leave as is.
        • The default is Unchecked.
    • Block WAN Requests:
      • Block Anonymous WAN Requests (ping): Unchecked.
        • This optional step is needed to allow the router to respond to our Call Quality Monitoring and Troubleshooting Server, 64.28.122.100.
      • Filter Multicast: Checked.
        • This is recommended but optional.
      • Filter WAN NAT Redirection: Unchecked.
        • This is recommended but optional.
      • Filter IDENT (Port 113): Checked.
        • This is recommended but optional.
      • Block WAN SNMP access: Checked.
        • This is recommended but optional.
    • Impede WAN DoS/Brutforce.
      • Limit SSH Access: Checked.
        • This is recommended but optional.
      • Limit Telnet Access: Checked.
        • This is recommended but optional.
      • Limit PPTP Server Access: Checked.
        • This is recommended but optional.
      • Limit FTP Server Access: Checked.
        • This is recommended but optional.
    • Click on Save at the bottom of the page.
  4. The steps below are required to prevent and resolve call/fax audio quality issues:
    • Go to NAT/QoS > QoS > Do the following:
      • Start QoS: Enable.
      • Port: WAN.
      • Packet Scheduler: HTB.
      • Uplink (kbps): Set this to 80-95% of your max Upload bandwidth limit.
        • Take the average of 3 bandwidth tests at speedtest.net if you do not know.
      • Downlink (kbps): Set this to 80-95% of your max Download bandwidth limit.
        • Take the average of 3 bandwidth tests at speedtest.net if you do not know.
      • Click Save at the bottom of the page.
      • On the same QoS page, go to Services Priority.
        • Click Add/Edit Service.
        • A new pop-up window will open.  Enter each rule one-by-one:
          • Call/Fax Audio Rule:
            • Service Name: "CloudVoiceRTP".
            • Protocol: UDP.
            • Port Range: 30000 ~ 50000.
            • Click Add.
          • Phone/Fax Local Registration Port Rule:
            • Service Name: "CloudVoiceSIPLocal".
            • Protocol: UDP.
            • Port Range: 6100 ~ 6899.
            • Click Add.
          • Phone/Fax Remote Registration Port Rule:
            • Service Name: "CloudVoiceSIPMain".
            • Protocol: UDP.
            • Port Range: 6060 ~ 6061.
            • Click Add.
          • Click Apply Settings.  The pop-up window will close.
          • Under Services Priority on the same page:
          • Click on the drop-down box next to Add:
            • Select "CloudVoiceRTP".
            • Click Add.
            • Set Priority to Premium.
          • Click on the same drop-down box again:
            • Select "CloudVoiceSIPLocal".
            • Click Add.
            • Set Priority to Premium.
          • Click on the same drop-down box again:
            • Select "CloudVoiceSIPMain".
            • Click Add.
            • Set Priority to Premium.
          • Click Apply Settings at the bottom of the page.
            • This causes the changes to take effect immediately.
            • Do not click Save, unless you do not want the changes to take effect until you click Apply.
            • All services that do not have Priority rules added will be set to the Standard Priority Level by default.
            • We strongly recommend that you do not add any other devices to the Premium Priority Level except for the phone/fax rules above.
          • If you still expereince call audio issues after these changes:
            • You will need to add phone & fax device to the MAC Priority section.
            • You will need to set each phone & fax device to use a Manual Priority & set the Max WAN Down & Up speed to 100kbps.
  5. These steps are only needed if you have or plan to purchase Polycom phones:
    • Go to Setup > Basic Setup tab.
    • Scoll down to Network Address Server Settings (DHCP). 
    • Change the following:
      • Static DNS 1: "8.8.8.8".
      • Static DNS 2: "8.8.4.4".
      • Use DNSMasq for DHCP: Uncheck.
      • Use DNSMasq for DNS: Un-check this if you have Polycom phones. Otherwise, leave it checked.
      • DHCP-Authoritative: Uncheck.
    • Click on Save at the bottom of the page.
    • Reboot the router, all phones and fax devices.
      • If any computers or other devices cannot load websites after the changes above, reboot them.

Permanent Resolution

  1. Search the DD-WRT router database to confirm if your router make/model/revision is supported.
    • If your model is listed as supported, no further changes are required.
    • If your model is listed as not supported or is WIP (work-in-progress), follow these steps:
      • Replace your router with a different serviceable or 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 assist 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.

Troubleshooting

Since these devices are open source Linux based routers you can use them for advanced troubleshooting. If you'd like to know more, read this article about using the tcpdump command to conduct a packet capture.