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    DHCP and DNS in routed network

    Scheduled Pinned Locked Moved DHCP and DNS
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    • S
      SteveITS Galactic Empire @Ethereal
      last edited by

      @Ethereal Something else would have to relay.

      DHCP is basically the device asking “can anyone give me an address?” If there were two DHCP servers on a network with different settings, either may answer first.

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      • E
        Ethereal @SteveITS
        last edited by

        @SteveITS the relay is always done by the router of the network where the host asking for a lease, sits. These frames are L2 and don't go outside the broadcast domain.

        S johnpozJ 2 Replies Last reply Reply Quote 0
        • S
          SteveITS Galactic Empire @Ethereal
          last edited by

          @Ethereal ok but in this scenario that’s not pfSense, correct? If the request is forwarded to pfSense how does pfSense know for what other network it should answer?

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          • johnpozJ
            johnpoz LAYER 8 Global Moderator @Ethereal
            last edited by

            @Ethereal pfsense does not support setting a scope for a non directly connected network maybe with the dhcpd that is coming they will that function?

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            • AndyRHA
              AndyRH @SteveITS
              last edited by

              @SteveITS said in DHCP and DNS in routed network:

              If the request is forwarded to pfSense how does pfSense know for what other network it should answer?

              If pfSense did support this common feature, the relay sees the broadcast, sends a directed packet to the DHCP server including subnet information. The DHCP server responds with the lease information. The relay then responds with a broadcast to the original requester with the DHCP lease information. Works great in large networks.
              Maybe the rumors of a change in DHCP server for pfSense will add this feature.

              o||||o
              7100-1u

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              • E
                Ethereal @AndyRH
                last edited by

                @AndyRH I'm glad to see that there are many people out there asking for this feature to be implemented.

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                • S
                  SteveITS Galactic Empire @Ethereal
                  last edited by

                  I understand the request now. In a very quick search I found this 7 year old thread saying it doesn't work in Kea but maybe they have added it since.

                  https://lists.isc.org/mailman/htdig/kea-users/2016-December/000707.html

                  ref: Replace ISC DHCP server with Kea: https://redmine.pfsense.org/issues/6960

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                  • johnpozJ
                    johnpoz LAYER 8 Global Moderator @Ethereal
                    last edited by johnpoz

                    @Ethereal said in DHCP and DNS in routed network:

                    many people

                    Define many? If you mean a few here and there as many - ok ;) hehehe

                    Most networks that get to the stage that they are routing downstream run their own dhcpd, and not off their edge router..

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                    Please don't Chat/PM me for help, unless mod related
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                    • AndyRHA
                      AndyRH
                      last edited by

                      If you use the Customer Service complaint theory, only a low percentage of people will complain, most just go somewhere else.
                      In the last few months I have seen 3 or 4 posts in some way related to DHCP relay. So 3 times some number that just do something else. That total has to be more than a few dozen. Enough to warrant adding the feature, maybe. If relay is a feature of KEA (I have found no evidence it is) then it would be wise to implement it.
                      In a lab environment relay would be nice so it can be used for practice.
                      I am more after the feature to add a reservation in the range, which appears to be a feature. It just makes it easier for me and I do not have IP address OCD so I am cool with "random" reservations.

                      o||||o
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                      • E
                        Ethereal @johnpoz
                        last edited by

                        @johnpoz hahahaha yeah, well in my defense there are a few posts on this forum around this feature. People (like me) are a bit surprised that this is not supported and in the same time a bit disapointed, since it's quite a basic feature.
                        In the same time, you're not wrong about the dedicated DHCP server.
                        Myself I have the scopes configured on my 3750x switch, however would love to have them configured on the pfsense box. I love the gui, I can't help it.

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