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    How to create logical subnets with a single Lan interface without VLAN?

    Scheduled Pinned Locked Moved NAT
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    • DerelictD
      Derelict LAYER 8 Netgate
      last edited by

      Any security you think you're getting from your proposed solution is an illusion.

      Any host can just change its IP address to one of the other subnet schemes and they're now on that "LAN."

      Traffic among the "different LANs" is not dependent on pfSense's firewall to forward.  Any host can also add VIPs on all three subnets and access any host on any subnet at any time and there's not a damn thing your firewall can do about it, because it's not being routed through.

      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)

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      • C
        cceraja
        last edited by

        Hi,

        The client is ok with that.. Users are not given admin rights to the pcs/registry and hence can't change the IPs.

        Mac ID for each PCs are also in place.

        Believe me or not.. They have been running this setup for past 3 years without any issues.

        Regards,
        Raja

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        • DerelictD
          Derelict LAYER 8 Netgate
          last edited by

          OK.  Good luck.

          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)

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          • K
            kejianshi
            last edited by

            ;D

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            • K
              kejianshi
              last edited by

              Derelict - Are you saying that putting the 3 switches in 3 separate VLANs will not work for isolating them from each other?

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              • DerelictD
                Derelict LAYER 8 Netgate
                last edited by

                No.  That absolutely will, providing one doesn't want different VLANs on the same unmanaged edge switch.

                Nothing wrong with the attached config if you can tolerate unmanaged switches in your network.

                VLANs.png
                VLANs.png_thumb

                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)

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                • K
                  kejianshi
                  last edited by

                  Cool - You scared me for a minute.  Occasionally my thinking gets a correction here…
                  Last time I thought I knew something absolutely for sure, I ended up getting punked by CMB.  haha.
                  I'm not sure why OP is so opposed to VLANS, but what he said about the client computers being locked down gave me this idea:

                  Assuming he is correct and the network is PHYSICALLY secure.  No one can plug/unplug things and the machines are truly secured and no config changes can be made, he could just control what can and can not be accessed on each client machine's firewall.  Seems to me the only other way to do it.  Other than running 3 separate LAN NICs or VLANs.

                  I wouldn't recommend that though.

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                  • DerelictD
                    Derelict LAYER 8 Netgate
                    last edited by

                    VLANs are far easier than maintaining the necessary MAC address lists.  And since MACs can be easily spoofed, far more effective.

                    US$500 gets managed switches all around (cheap ones, but light years better than the proposed hack).

                    Dude doesn't want to listen and that's fine with me.  I'm not the one on call when it blows up.

                    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)

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                    • K
                      kejianshi
                      last edited by

                      Even at $500 he would be doing himself a favor.

                      But seriously, for $30 to $50 he could get a VERY nice used managed gigabit switch with a ton of ports from someone on ebay who is upgrading to 10GB…

                      You think I make a habit of buying all new hardware?  I'd be broke...  I have stuff everywhere.

                      (I buy hardware for people with the condition to run my services on their bandwidth)

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                      • C
                        cceraja
                        last edited by

                        Hi,

                        Mac can be spoofed.. Even vlans are not secure. A determined person can still put a plug on vlan port can still gain access to the vlan. But Iam not going into this now. And its hard for me to convince my client to buy additional hardwares. He has been living with this network for years.

                        If my configuration will work, why is that I have problems when configuring gateway groups( load balancing) in pfsense. Is this a known issue with pfsense? Whennever I configure gateway groups, the first hop always goes to the wan router instead of my pfsense router. I believe it should be a simple routing issue. Not sure how to fix this. I am just new to pfsense.

                        Regards,
                        Raja

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                        • johnpozJ
                          johnpoz LAYER 8 Global Moderator
                          last edited by

                          You don't run multiple layer 3 over the same layer 2 - you do not do this, this is wrong.. I don't care what the client says.  Why do they even think it is possible??  Let them setup their own network then - I wouldn't have anything to do with this.  If they are so freaking cheap they wont spend pennies to get the correct hardware - they sure and the hell can not be paying you anything worth doing something this wrong!!

                          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 2.7.2, 24.11

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                          • DerelictD
                            Derelict LAYER 8 Netgate
                            last edited by

                            @cceraja:

                            Is this a known issue with pfsense? Whennever I configure gateway groups, the first hop always goes to the wan router instead of my pfsense router. I believe it should be a simple routing issue. Not sure how to fix this. I am just new to pfsense.

                            No.  It's a known issue with hokey, broken network design.  All sorts of wacky crap will happen.  Expect 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)

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

                              @cceraja:

                              Even vlans are not secure. A determined person can still put a plug on vlan port can still gain access to the vlan.

                              Umm, yes.  Plug into an enabled port on the VLAN and you're on the VLAN.  That's sort of the point.  Controlling such access is a completely separate problem, which might be solved using 802.1x if that's what you're worried about.  You'd need managed switches though.  ;)

                              If you're talking about VLAN hopping I'll need to see an example with modern gear to believe it's still a viable hack.

                              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)

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                              • johnpozJ
                                johnpoz LAYER 8 Global Moderator
                                last edited by

                                @Derelict:

                                No.  It's a known issue with hokey, broken network design.  All sorts of wacky crap will happen.  Expect it.

                                Oh that made my morning!!  Always good to start the day with a laugh!! ;) heheeheheh

                                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 2.7.2, 24.11

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                                • H
                                  Harvy66
                                  last edited by

                                  @cceraja:

                                  Hello Derelict,

                                  I agree that it may not be a standard way. But still when a feature is there why not exploit it?

                                  Look at the advantage it has… You don't need additional switches and additional nic for subnets.

                                  Regards,
                                  Raja

                                  That's not a feature, it's an undefined configuration that is highly recommended against. Kind of like people using a high or low IP address of a subnet. It can work in some setups, but expect strange stuff to happen.

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