OpenVPN with UPNP = Double NAT/Strict NAT?



  • I'm far from a network guru, I'm a hardware guy and having trouble figuring this out.

    I am using Pfsense to replace my Ubiquiti Edgerouter X as I want to run a VPN 24/7 for one of my VLANs. Basically I have a teen who keeps getting DDOSed while paying xbox games. Apparently it's a thing now and pretty easy to do.

    My network consists of...

    -Gigabit Comcast (1Gbps down/40Mbps up).
    -Netgear CM1000 modem connected to WAN.
    -Pfsense Box with WAN in and one trunked LAN out.
    -Mikrotik 10G switch where everything else connects.
    -Two TP Link Omada WAPs/3 unmanaged switches.

    Primary network LAN 192.168.2.0
    VLAN 10 192.168.1.0
    VLAN 20 192.168.4.0

    When I set up my pfsense and add a rule to allow all traffic on VLANs, all current devices appear to connect and work as they should on their respective networks.... When I start to mix UPNP and openVPN is where the issues start.

    So after playing around for about 4 hours tonight I found some more details and specifics of what's causing it. If I keep the my client openVPN through private internet access off, I can enable UPNP and with the rules in my NAT outbound settings, and my gaming Alias with multiple IPs it works perfect.

    If I turn openvpn on with the associated rules and UPNP off, I get a normal but strict NAT type.

    If I run openvpn with UPNP both on, I get a report of a double NAT that is strict and I can't solve it.

    TL:DR

    OpenVPN off, UPNP on = Open NAT yayyy!
    OpenVPN on, UPNP off = Strict NAT
    OpenVPN on, UPNP on = Double NAT, strict 😡


  • Netgate Administrator

    You will always see double NAT through OpenVPN unless you have paid to get a public IP which some services offer I believe.
    UPNP does not pass requests upstream so you can cannot open ports on the VPN, it will never appear as open.
    You need to set static outbound NAT for the xbox both out the WAN and over the VPN.

    Steve


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