Ping error: Invalid Argument

  • Hello!

    My OPT1 interface is not working. It has ip address, and when I ping, it does not work and the answer is: Invalid Argument.

    LAN's ip address is is network that I need reach from


  • Can you draw a diagram?
    I dont really get, which subnet is where.

  • I hope this diagram help us….

    The network that is connected to the OPT1 interface, its a network that already has its own gateway. I just want to route traffic from LAN to OPT1 network. But I can't even ping any host on network.


  • Um…. this will never work.
    How are your clients in the 10.10.140.x/24 subnet supposed to know the route to the 10.10.170.x/24 subnet if they have another gateway?

    You have several possibilities to solve this.
    1: set the gateway to the OPT1 IP. --> the easiest. But if you NEED to have another gateway, not applicable in your case.
    2: create static route entries on the clients in the 10.10.140.x/24 subnet. Point the 10.10.170.x/24 subnet to the OPT1 IP . --> not recommended.
    3: create a static route entry on the gateway in your 10.10.140.x/24 subnet. --> doable. i would go with this way.
    4: enable NAT from 10.10.140.x/24 to 10.10.170.x/24 --> like this requests from your LAN to the OPT1 subnet appear as if from the OPT1-interface itself. --> you only want that if you need access from LAN subnet to the OPT1 subnet. Access from OPT1 subnet to the LAN subnet is only possible if you create other NAT entries from OPT1 to LAN. in my opinion as good as the 3rd solution, but requires knowledge about NAT. Also the source will always appear as if fromt the router interface itself. --> not good in many cases.

  • to make things easy, I made another topology that I believe is better than the other one…

    I got Firewall1 and Firewall2, and what I want is make both LANs reach themselves... Then I created another network to connect Firewall1 to Firewall2... I also created an static route on both Firewalls:

    Firewall1 -> when destiny is goes through (OPT1)
    Firewall2 -> when destiny is goes through (OPT1)

    Looks like things are okay, but i can't ping from Firewall1 to Firewall2 and even from Firewall2 to Firewall1. I was using a VLAN on my switch and to make sure there was no pŕoblem in "the way" (cables, switches) i made a cross cable to connect the firewalls directly.

  • I forgot to say that the "Invalid Argument" error message is not appearing any more….
    just "100% packet lost"....

  • Did you create rules on the respective interfaces that allow traffic?
    ie. on the interface you have to create a rule that allows traffic to the ubnet if the source is

  • Both OPT1 interfaces were already allowing traffic from any to any…

    Firewall1 can't ping Firewall2 through directly connected interfaces... It seems like OPT1 interfaces are blocked or something like that...

    Couple days ago I've tried to build a multi-wan Firewall and the same thing happened: OPT1 couldn't find its gateway, and it was also directly connected with correct ip addressing...

  • Can you show screenshots of your OPT firewall rules?

    If you cannot ping the interface directly you missconfigured the firewall rule.

    You say you connect the interfaces directly.
    Did you make sure that you're using a crossover cable?

    Can you verify that you can ping the interface through putting a computer in front of the OPT interface and ping it?

  • I did make sure that I'm using a crossover cable, and I also checked that it is working fine…
    I never saw something like that...

    Here are the screenshots of Firewall1 and Firewall2 OPT rules. There is no comunication between both interfaces. I feel like I'm doing some idiot mistake...

    If you could help, I will be glad.

  • You missunderstand what the gateway means.

    It means if traffic on this interface comes in and matches the rule it will be send to the gateway.
    If you set * (default) it will be processes by the routingtable of pfSense.
    Right now you force the traffic somewhere.
    But inbound on the interface itself that doesnt make any sense.

    As a rule of thumb you can say: never edit the gateway unless you REALLY know that you want to force traffic this way.
    It's usually better to add static routes to the routing table and let the gateway on *.

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