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How to configure RV042 for double NAT

Discussion in 'Cisco Small Business Routers and VPN Solutions' started by markd89, Mar 28, 2008.

  1. markd89

    markd89 Addicted to LI Member

    I'm using the RV042 for the dual-WAN capability, not to do VPN stuff.

    I set the RV042 to be (

    I set my DHCP cable modem as one WAN connection. The DHCP cable modem gives the RV042 a "real IP" address. This works fine. I unplugged it from RV042 so I know I am trying to go over the second WAN connection.

    For my other WAN connection, I plug in a DHCP DSL Router. This thing does not give a "real IP" because it is already doing NAT. The DSL Router is set to be ( I set the RV042 to be a static IP of to use a gateway of No joy.

    If I plug in a PC with these IP settings, then I can access the internet. There must be a setting in the RV042 that I need to do to make it route correctly with the double NAT.

    Any suggestions greatly appreciated!

  2. vpnuser

    vpnuser LI Guru Member

    What's the DNS Server your RV042's WAN is configured with?
  3. markd89

    markd89 Addicted to LI Member

    WAN2 (the one I am using for this) is set to use (the DSL router) and (Verizon) as DNS.

    I don't think it is a DNS issue because I cannot ping outside IPs directly either.

    I appreciate any suggestions.

  4. Sfor

    Sfor Network Guru Member

    According to your description everything should work without any other settings. As, there is no "double NAT" or anything like that.

    You should provide more informations about your RV042, cable modem and DSL router settings. Especialy WAN and LAN IP of the routers.

    Quite significant are also: Setup - Network - Dual-WAN / DMZ Setting and System Management - Dual-WAN
  5. markd89

    markd89 Addicted to LI Member

    Setup Screen:

    domain name:
    Device IP /

    Dual WAN/DMZ - Set to Dual WAN.

    WAN 1 (this is the cable modem and it works OK)
    Obtain IP Address Automatically

    WAN2 (this is the problem DSL router)
    Static IP

    WAN IP Address /
    Subnet Mask

    Mode: Gateway

    To test, I unplug WAN1 and then I can't access the internet.

    I have also tried setting WAN2 as Obtain IP Address Automatically. When I do this, it doesn't get an IP. If I plug in a PC with the same settings, I get an IP and all is happy.
  6. Sfor

    Sfor Network Guru Member

    Did you try to connect the DSL to the WAN1? (Perhaps the WAN2 port is damaged.)

    Also, what is the System Management - Dual-WAN setting?
  7. jwab

    jwab Addicted to LI Member

    Hey Markd89, did you resolve this? If so what was the solution?
  8. DocLarge

    DocLarge Super Moderator Staff Member Member

    The best solution I know (having been put into this situation recently) is to put the dsl modem into "bridge mode." Once you do this, the RV042 will need to do the PPPoE/PPPoA username and password authentication (which it should do). I'm doing this with my WRVS4400N at the moment. Additionally, if you're offering any services (i.e., FTP/DNS/Mail Server(s)) you'll need to see if you can get a static ip instead of the DHCP assigned address. Reason being, everytime the router reboots, it pulls a different ip which is bad if you do have servers in your environment.

    What type of dsl modem do you have (in case I missed it)?

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