Netgate Discussion Forum
    • Categories
    • Recent
    • Tags
    • Popular
    • Users
    • Search
    • Register
    • Login
    Introducing Netgate Nexus: Multi-Instance Management at Your Fingertips.

    Spoofing MAC Addresses

    Scheduled Pinned Locked Moved Firewalling
    2 Posts 2 Posters 1.6k Views
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • R Offline
      rjarratt
      last edited by

      I am a bit of a newbie to pfSense and not a professional admin, so please be patient if I ask something stupid.

      I am using pfSense as my home firewall, hosted on a Hyper-V server. I have some software that I want to run on the pfSense VM that sends packets out onto my local LAN using libpcap. The packets are not IP and must be able to change the source MAC address (in case anyone is curious, it is a user mode DECnet router). The packets appear to be getting stopped somewhere, most likely the firewall, but I can't be sure. I have enabled MAC spoofing in the Hyper-V settings for the interface.

      Is this something that could possibly work, or am I hitting a fundamental "by design" issue that cannot be resolved?

      Thanks

      Rob

      1 Reply Last reply Reply Quote 0
      • jimpJ Offline
        jimp Rebel Alliance Developer Netgate
        last edited by

        pfSense would not/could not stop that. It doesn't filter at L2 (unless you have captive portal enabled).

        You can confirm if the packets leave the firewall by running a packet capture while running the software.

        More likely it's being blocked/dropped by Hyper-V, not pfSense.

        Remember: Upvote with the 👍 button for any user/post you find to be helpful, informative, or deserving of recognition!

        Need help fast? Netgate Global Support!

        Do not Chat/PM for help!

        1 Reply Last reply Reply Quote 0
        • First post
          Last post
        Copyright 2026 Rubicon Communications LLC (Netgate). All rights reserved.
        Privacy Policy · Cookie Policy