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    2 bridged networks / DHCP problem

    Scheduled Pinned Locked Moved DHCP and DNS
    12 Posts 4 Posters 10.5k Views
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    • G Offline
      gbenoit
      last edited by

      Do you see DHCPDISCOVER request on both DHCP server ?

      On my side, how it seems to work :

      1 - laptop makes DHCPDISCOVER request
      2 - both dhcp server send a DHCPOFFER
      3 - laptop makes a DHCPREQUEST with the first offered IP it received (let's say DHCP 1)
      4a - DHCP 1 confirm with a DHCPACK
      4b - DHCP 2 logs "unknow lease"

      So laptop is connected through DHCP 1

      Nota : DHCP 2 says unknow lease and not wrong network because both are sharing the same IP network (but distributing only half of the network range).

      On which DHCP server do you see "wrong network" message ?

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      • H Offline
        hchady
        last edited by

        on DHCP 1 (134.214.0.0/22) pfsense record these logs :

        Apr 26 18:10:23 dhcpd: DHCPDISCOVER from 00:90:96:20:98:2d via rl0: network 134.214.0/22: no free leases
        Apr 26 18:10:23 dhcpd: DHCPREQUEST for 134.214.232.32 (134.214.100.6) from 00:90:96:20:98:2d via rl0: wrong network.
        Apr 26 18:10:23 dhcpd: DHCPNAK on 134.214.232.32 to 00:90:96:20:98:2d via rl0
        Apr 26 18:10:24 dhcpd: DHCPDISCOVER from 00:90:96:20:98:2d via rl0: network 134.214.0/22: no free leases
        Apr 26 18:10:24 dhcpd: DHCPREQUEST for 134.214.232.32 (134.214.100.6) from 00:90:96:20:98:2d via rl0: wrong network.
        Apr 26 18:10:24 dhcpd: DHCPNAK on 134.214.232.32 to 00:90:96:20:98:2d via rl0

        I don't have access to the logs of DHCP2 (134.214.100.6), but it seems that it offer the IP 134.214.232.32 to the client.
        if I restart or stop the pfsense DHCP, the client gets the IP 134.214.232.32 directely.

        note that DHCP 1 cannot offer a lease for an unknown client because the option deny unknown option is checked.

        So any idea ?

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        • G Offline
          gbenoit
          last edited by

          OK, maybe the DHCPNACK cancels the DHCPACK from the other dhcp server.

          As you're using public IPs, maybe it will be difficult, but if you can try  to extend the subnet of the DHCP 1 (let's say from /22 et /16), to include the network of the second DHCP server in the same network as the first (same network, but still different ranges), in order to see if the "unknow lease" only instead of the DHCPNACK message should solve the issue…

          Because DHCPNACK is sent to client, but unknow lease is only log, and no message is sent back to client.

          DHCPNACK is used to say to a laptop coming from another wifi network : "hey, you're dhcp renew is not valid on this wifi lan ! you're no more on your home wifi network"

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          • H Offline
            hchady
            last edited by

            i think that it is something related to dhcp-authoritative option that is not enabled may be on DHCP 2 (Windows 2K3 server)

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            • G Offline
              gbenoit
              last edited by

              And I still think it might be a DHCPNACK issue  :D

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              • H Offline
                hchady
                last edited by

                hmmm !! ok

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                • H Offline
                  hchady
                  last edited by

                  is there a solution for this ?

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                  • J Offline
                    jeroen234
                    last edited by

                    using only 1 dhcp server

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                    • G Offline
                      gbenoit
                      last edited by

                      Map wireless lan on different VLAN, or try to share the same network, and dhcp distributing on 2 different ranges.

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                      • H Offline
                        hchady
                        last edited by

                        the problem that i have 2 differents servers for authentication, and a captive portal on each network
                        so is there a way to let user choose between the server, or the domain ?

                        i.e. there is a way to have local authentication and radius or NT domaine (or LDAP) authentication on the same captive portal page ?
                        in this way each user can choice his domain

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                        • H Offline
                          hoba
                          last edited by

                          No. Maybe you can try to simplyfiy your setup a bit. It seems to be rather complex.

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