Netgate Discussion Forum
    • Categories
    • Recent
    • Tags
    • Popular
    • Users
    • Search
    • Register
    • Login

    Static Mapping and IP conflict.

    Scheduled Pinned Locked Moved DHCP and DNS
    6 Posts 4 Posters 1.8k 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.
    • O
      oguruma
      last edited by

      I am running 2.2.6 connected as follows: ISP Modem > PFSense >Unmanaged Switch > Wifi Router and Clients

      I used PFsense to map a static IP to my Macbook. It was working fine, until my Amazon FireTV connected, and somehow got assigned the same IP as the Macbook. The Wifi Router is a Netgear, and the DHCP server is turned off. The FireTV doesn't have a static IP. What assigned the FireTV the same IP as my Macbook if the Macbook has been mapped to that IP, and there is no other DHCP server on the network?

      1 Reply Last reply Reply Quote 0
      • M
        muswellhillbilly
        last edited by

        If your FireTV has picked up a DHCP address, then obviously there is a DCHP server operating on your network, whether you're aware of it or not. Why not put a Windows/Linux machine on your network with the network settings set to dynamic and see if it picks up an address? You only have to then run an 'ipconfig /all' to find out the IP of the DHCP server handing out the addresses.

        1 Reply Last reply Reply Quote 0
        • johnpozJ
          johnpoz LAYER 8 Global Moderator
          last edited by

          here is a nice little tool to just look for dhcp servers..

          https://github.com/CyberShadow/dhcptest

          you send out a discover packet and see what you get back..

          Since static mappings with pfsense are outside the scope.. It would seem impossible for pfsense to have handed out that duplicate - so that points to a different dhcp server..  To be honest a client getting a dupe should be pretty hard since many dhcp server and clients look to see if anyone has the IP before they actually use it or hand it out.

          dhcptestpng.png
          dhcptestpng.png_thumb

          An intelligent man is sometimes forced to be drunk to spend time with his fools
          If you get confused: Listen to the Music Play
          Please don't Chat/PM me for help, unless mod related
          SG-4860 24.11 | Lab VMs 2.8, 24.11

          1 Reply Last reply Reply Quote 0
          • O
            oguruma
            last edited by

            Something goofy happened. I was using the Macbook with an IP mapped to .29, walked away for 30 minutes, came back and received error message "another device on the network has the same IP". Logged into the PFsense GUI and sure enough the Fire was assigned .29….

            1 Reply Last reply Reply Quote 0
            • DerelictD
              Derelict LAYER 8 Netgate
              last edited by

              ISC dhcpd will not do that. You likely have another DHCP server on your network.

              Chattanooga, Tennessee, USA
              A comprehensive network diagram is worth 10,000 words and 15 conference calls.
              DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
              Do Not Chat For Help! NO_WAN_EGRESS(TM)

              1 Reply Last reply Reply Quote 0
              • M
                muswellhillbilly
                last edited by

                @oguruma:

                Something goofy happened. I was using the Macbook with an IP mapped to .29, walked away for 30 minutes, came back and received error message "another device on the network has the same IP". Logged into the PFsense GUI and sure enough the Fire was assigned .29….

                Well, you've had a couple of suggestions already about what to do. Given them a try and see how you get on.

                1 Reply Last reply Reply Quote 0
                • First post
                  Last post
                Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.