Recommendation Information

This device does not have WiFi.  You will need to install a separate wireless AP if you need wireless.
This device is different from the Linksys RV042/RV042G, the Cisco RV042G, and the Cisco RV042-Hardware-Version-1-or-2.
Price: ~$150

  • The Cisco RV042-Hardware-Version-3 running the v4.2.3.03 firmware disables SIP ALG, which is exactly what the phones need.  If your model isn't running that firmware version, you or your IT will need to upgrade the firmware to v4.2.3.03 or higher.  If you need help, contact Cisco.
  • This router has a powerful Bandwidth Management (also known as Rate Control) system that allows reserving the exact amount of the bandwidth the phones need. 
  • This model was confirmed to be effective at maintaining crystal clear audio, even when the customer's internet connection was purposely being maxed out.
  • The other RV-models likely have the same system, but you will need to upgrade them to firmware v. or higher for them to work correctly.
  • The RV042-Hardware-Version-3 can be hard to find.

Known Issues

  1. SIP ALG is enabled by default on most firmware versions that are older than, but in, SIP ALG is disabled, which is what we want.
  2. The MTU is set to Auto by default, but many Cisco routers automatically set the MTU too low -- for example to 576 on some of our customer's routers -- which causes intermittent phone feature failures & audio to cut out mid-calls.
  3. The firmware on this series of routers are very buggy, but Cisco has worked hard to resolve most of the VoIP-related problems in their 2014 firmware releases.  It's critical to upgrade these routers to the latest firmware version to avoid strange call audio and phone registration issues.


  1. Log into the router.
  2. On the System Summary page > System Information > PID VID > Verify that this shows RV042 V03. 
    • If you do not see the V03, then you do not have a RV042-Hardware-Version-3 and this article does not apply to your router.
  3. Upgrade your router's firmware to v4.2.3.03 or higher:
    • This is needed to disable SIP ALG and resolve many intermittent call audio and registration-related firmware problems.
    • Intermedia cannot do this for you because we cannot be held liable if the firmware upgrade fails, but you can contact your IT or call Cisco and they can help guide you through the process.
      • Backup your router settings first:
        • Go to System Management > Backup and Restore > Backup Configuration File:
        • Backup Startup Configuration: Click this button and save the file to your computer
        • Backup Mirror Configuration: Click this button and save the file to your computer.
      • Go to System Management > Firmware Upgrade > Firmware Download > Click Firmware Download from Web Site > Dowload the latest firmware to your computer -- it should be or higher.
        • Prepare to upgrade the router's firmware. 
        • Do this at a time when you can afford to take your entire network down for 10 minutes or longer if something goes wrong.
        • If people are using their computers, warn them to save their work.
      • Go back into the router > System Management > Firmware Upgrade > Firmware Upgrade > Choose File > Find the firmware file that you downloaded to your computer > Click Open > Click Upgrade.
        • Wait 5-10 minutes while the router upgrades.
        • Do not powercycle or interrupt the router during this process.
          • If the router does not come back online after 20 minutes, call Cisco because this indicates the your router failed to accept the firmware upgrade and may be faulty.
        • After the router page refreshes, log back in.
        • On the System Summary page > System Information > Firmware Version > Verify the version is v4.2.3.03 or higher.
  4. This step is needed for call quality monitoring and troubleshooting purposes.
    • Go to Firewall > General > Set the following:
      • Firewall: Leave Enabled
      • SPI (Stateful Packet Inspection): Leave Enabled
      • DoS (Denial of Service): Leave Enabled
      • Block WAN Request: Leave Enabled
      • Leave all other firewall settings on this page unchanged.
      • Click Save at the bottom of the page.
    • Go to Firewall > Access Rules > Click Add > Set the following:
      • Action: Allow
      • Service: Ping (ICMP/255~255)
      • Log: Log packets match this rule
      • Source Interface: ANY
      • Source IP -> IP Address ->
      • Destination IP: ANY
      • Scheduling
        • Time: Always
      • Click Save
      • Repeat the previous steps for IP address
  5. This step is only needed if you have or plan to purchase Polycom phones:
    • This change will take your computers and phones offline. 
    • The phones and computers will need to be rebooted after making these changes.
      • Go to DHCP > DHCP Setup > Scoll down to DNS:
        • DNS Server: Select "Use DNS as Below"
          • This option will only show in newer firmware versions. 
          • If you don't have this option, you need to upgrade your router's firmware to v4.2.3.03 or higher before making these DNS changes.
        • Static DNS 1:
        • Static DNS 2:
        • Click Save
  6. This step is needed to reserve the exact amount of bandwidth the phones need to prevent call quality problems:
    1. Go to DHCP > DHCP Setup > IPv4 > See if the checkbox "Enable DHCP Server" is already checked:
      1. If it is *not* checked, then:
        • This means your DHCP server is running on a separate device, like a Windows Server or another router. 
        • You or your IT will need to setup DHCP IP reservations on that separate DHCP server before you can proceed to step 6B.
      2. If it *is* checked, then scroll down to Dynamic IP:
        • Write down what the Range Start & Range End are.  You will need this in the next step.
      3. Scoll down to Static IP > Enter the following:
        1. Static IP Address: Enter in the first IP address you'd like your first Intermedia device to use. 
          • This needs to be an IP that is not already in-use by another device and needs to be one that is within your DHCP range that you noted in the previous step. 
          • Try to select an IP that is at the start of a block that all Intermedia devices can use.
          • Example: For phone extension 100, we entered and will be assigning to for our 21 phones to use.
        2. MAC Address: Enter in the MAC address of the phone
        3. Name: VoIPDevice1
          • This field has a 12-character limit, so each device will needed to be numbered 1 and above.
        4. Enable: Check this box
        5. Click Add to List
        6. Repeat steps 3a - 3e until all Intermedia phones, fax adapters, and other devices are added. 
          • Set each phone's IP address to fit a consecutive series.
        7. Scroll down to the bottom of the page > Click Save.
    2. Go to System Management > Dual WAN > The Max Bandwidth Provided by ISP > Click the Edit/Pencil button next to WAN1 > Enter the following:
      1. Interface: WAN1
      2. Upstream: Enter in upload speed you are paying your ISP for. 
        1. If you do not know, you will need to either:
          1. Call your ISP to obtain your actual speeds, or
          2. Run several bandwidth tests at and estimate your speeds.
      3. Downstream: Enter in download speed you are paying your ISP for
        1. Note: We do not support the phone using a dynamically-load-balanced connection between 2 separate ISP circuits. 
        2. If you are doing this, you will need to:
          1. Consult with you IT or Cisco to either set your Dual WAN setup to Failover only if your primary WAN goes offline, or
          2. Setup rules to ensure the phone's traffic only goes out 1 WAN interface.
    3. Go to System Management > Bandwidth Management:
      1. The Maxiumum Bandwidth Provided by ISP
      2. Bandwidth Management Type:
      3. Scoll down to the bottom of the page > Click Save
  7. Backup your router settings again so you will not have to do this process again if your router experiences problems:
    • Go to System Management > Backup and Restore > Backup Configuration File:
      • Backup Startup Configuration: Click this button and save the file to your computer
      • Backup Mirror Configuration: Click this button and save the file to your computer.