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

Why does the UI allow duplicate IP addresses (different MACs) in DHCP static mappings?

Scheduled Pinned Locked Moved DHCP and DNS
6 Posts 2 Posters 903 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.
  • L
    luckman212 LAYER 8
    last edited by luckman212 Jun 8, 2022, 2:49 PM Jun 8, 2022, 1:54 PM

    Yesterday I was troubleshooting an issue where a VM was constantly losing it's connectivity (Windows machine, the famous "⚠️yellow exclamation mark"). After a lot of head scratching I finally realized it was a simple IP address conflict on the pfSense.

    I didn't realize that I'd mistakenly assigned the same static DHCP mappings to 2 VMs.

    I searched the git history for when this change was made, and found it here:

    • https://redmine.pfsense.org/issues/8220
    • commit b260591

    Can I ask what the reasoning is to allow this? I understand the corner case of a device with multiple interfaces (e.g. wired & wireless) where only one is supposed to be connected at any given time, and the user wants the IP to remain constant. But that is solveable in other ways. I think this is a potential footgun.

    It would be nice if at least a warning infoblock was printed after hitting Save.

    L 1 Reply Last reply Jun 8, 2022, 2:50 PM Reply Quote 0
    • L
      luckman212 LAYER 8 @luckman212
      last edited by luckman212 Jun 8, 2022, 2:51 PM Jun 8, 2022, 2:50 PM

      @jimp I submitted a PR for this: #4594

      1ac69e49-e449-4de0-8bd9-7c0b52ac4a24-image.png

      D 1 Reply Last reply Jun 8, 2022, 2:59 PM Reply Quote 0
      • D
        Derelict LAYER 8 Netgate @luckman212
        last edited by Derelict Jun 8, 2022, 3:00 PM Jun 8, 2022, 2:59 PM

        @luckman212 POLA dictates that checkbox should default to checked. Does it?

        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)

        L 1 Reply Last reply Jun 8, 2022, 3:06 PM Reply Quote 0
        • L
          luckman212 LAYER 8 @Derelict
          last edited by Jun 8, 2022, 3:06 PM

          @derelict Having it default to checked would negate the entire purpose of this change. POLA was not applied to the original commit, so I do not think it applies here either. I was more "astonished" when my DHCP was broken due to an address conflict.

          D 1 Reply Last reply Jun 8, 2022, 4:08 PM Reply Quote 0
          • D
            Derelict LAYER 8 Netgate @luckman212
            last edited by Jun 8, 2022, 4:08 PM

            @luckman212 As long as the behavior does not change for existing configurations.

            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)

            L 1 Reply Last reply Jun 8, 2022, 4:18 PM Reply Quote 0
            • L
              luckman212 LAYER 8 @Derelict
              last edited by Jun 8, 2022, 4:18 PM

              @derelict Correct—Nothing would change at all until the user actually goes in to edit an entry and either creates a new duplicate (or tries to save an existing one). At that point, the warning would be shown. All they have to do is check the box and re-save.

              1 Reply Last reply Reply Quote 0
              6 out of 6
              • First post
                6/6
                Last post
              Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.
                This community forum collects and processes your personal information.
                consent.not_received