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DHCP server of the wrong interface serves up IPs

Scheduled Pinned Locked Moved DHCP and DNS
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  • J
    Jarhead @DominikHoffmann
    last edited by Dec 24, 2022, 5:50 PM

    @dominikhoffmann said in DHCP server of the wrong interface serves up IPs:

    Correct! That’s how it is. Both are on physically separate switches, though, which is why this is all the more confounding.

    Why would that matter? As far as you said, the wireless is the only problem. The wired, which you say is on a separate switch, is fine, correct? So don't waste time with it. Look at the other switch.

    Are the AP(s) vlan capable?
    Are you sending the correct vlans?

    Maybe you have the SSID's misconfigured and you're actually connecting to the 'old' .14.0/24 network?

    Can you confirm the wifilan interface is set to the 15.0/24 network?

    D 1 Reply Last reply Dec 24, 2022, 6:15 PM Reply Quote 0
    • D
      DominikHoffmann @Jarhead
      last edited by DominikHoffmann Dec 24, 2022, 6:18 PM Dec 24, 2022, 6:15 PM

      @jarhead said in DHCP server of the wrong interface serves up IPs:

      Why would that matter? As far as you said, the wireless is the only problem. The wired, which you say is on a separate switch, is fine, correct? So don't waste time with it. Look at the other switch.

      As it is, I have seen hosts that had been on the physical switch on the 192.168.15.1/24 subnet reacquire the IP addresses they had obtained on that subnet, after they were physically connected to the switch on the 192.168.14.1/24 subnet. In other words, the DCHP server leakage across the subnets is bidirectional.

      Maybe you have the SSID's misconfigured and you're actually connecting to the 'old' .14.0/24 network?

      Can you confirm the wifilan interface is set to the 15.0/24 network?

      I cannot confirm that at the moment, because something is wrong with the VPN into that system. Still, all APs are on the 192.168.15.0/24 subnet as is evidenced in the UniFi OS Console managing them.

      J 1 Reply Last reply Dec 24, 2022, 6:49 PM Reply Quote 0
      • J
        Jarhead @DominikHoffmann
        last edited by Dec 24, 2022, 6:49 PM

        @dominikhoffmann
        Are you using Ubuiqiti switches?
        If so, you probably have each port set to "allow all vlans" maybe?
        Post screenshots of the switch configs

        D 1 Reply Last reply Dec 24, 2022, 6:52 PM Reply Quote 0
        • D
          DominikHoffmann @Jarhead
          last edited by Dec 24, 2022, 6:52 PM

          @jarhead said in DHCP server of the wrong interface serves up IPs:

          Are you using Ubuiqiti switches?

          The switches are Netgear switches. The VPN to that network is down right now, so I cannot show the VLAN setup there. However, There is a dedicated, physically separate switch for each subnet. Each switch has an IP address corresponding to the subnet it is physically on.

          The only Ubiquiti hardware are the APs and the console.

          1 Reply Last reply Reply Quote 0
          • D
            DominikHoffmann
            last edited by Feb 23, 2023, 1:33 AM

            I want to come back to this to post that I have solved this problem.

            My issue was that I had a bridge defined in Interfaces → Bridges. It bridged all my internal interfaces, except the guest and IoT interfaces. This allowed DCHP requests to leak through from one interface to the DHCP server running on another.

            Doh!

            I had done that, because I wanted to Bonjour-browse all my Apple devices, regardless of which subnet they were in. The Asahi package now accomplishes the same thing.

            1 Reply Last reply Reply Quote 0
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