IPV4 Network Tunnel config Issue

  • Hello All,

    I have an issue whereby I get the error: Options error: --server directive network/netmask combination is invalid

    Now I know what this relates to and its my IP config for the IPV4 Network Tunnel - I have set the IP

    If I change this to then the VPN connects - however as this is the incorrect subnet this will not allow VPN traffic to my LAN network.

    Has anyone got an idea as to what this could be ?

  • Is the tunnel network overlapping with LAN?
    What's your LAN network?

  • Hello,

    Yes it would be,

    My LAN Is

    My pool is

    I would like pfSense to use everything above as IPs for VPN clients.

    But the way to do this is not overly clear,

  • If the OpenVPN server is in tun mode the vpn tunnel network must not overlap other networks assigned to pfSense.
    So choose another network range for the tunnel.

  • @viragomann

    Thanks for that - sounds like I need in tap mode then ?
    I don’t know if tun will work as I haven’t set up any routing for it

  • I don't know, whats your intention with the OpenVPN server.

    In tun mode the server provides a tunnel network which work as transit network. Traffic meant to the remote site is to be routed to the other vpn endpoint. The server is capable to push routes to the clients.

    In tap mode the vpn interface can be bridge to another local network, e.g. LAN. So clients will get an IP of the LAN from the DHCP server.
    So to access remote LAN devices there is no route needed.

    Most challenges can be mastered with tun mode, which is the recommended one.

  • LAYER 8 Global Moderator

    @maverick-phillips said in IPV4 Network Tunnel config Issue:

    sounds like I need in tap mode then ?

    No not really - just sounds like you need to correctly setup your tunnel network. There is very few legit reasons where you would want to run tap mode.. Its not the recommended setup, nor is it even supported on some clients. For example the ios openvpn client does not support tap mode.

    Why do you think you need tap mode? And not just correctly setup tun mode?

  • Hello,

    Main reason is I have been trying for some time and i can’t get the configuration right.

    I would love to use Tun mode however with my understanding of how the IPV4 networks need to be setup I haven’t yet got it to work correctly.

    What would your suggestion be on the correct config for this ?

  • Key points to any routed VPN:

    • Tunnel subnet must be completely separate from any of you other subnets used, zero overlap allowed.

    • Let's the VPN system (OpenVPN in this case) manage the routing, read the OpenVPN documentation carefully, pay attention to --route, --push "route" and --iroute directives. On PfSense part of the routing is handled by the remote network configuration item (on a Remote Access Client or with a peer to peer setup), other parts have to be added to Advanced Configuration/Custom options.

  • By the way, tap mode changes almost nothing in the scenario. The only difference is that the tunnel network is no longer point-to-point and has broadcast semantics resembling a typical ethernet LAN. Client configuration and routing are still pretty much the same and if you can't get tun mode working properly you won't get tap mode working either.

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