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    Setting up my SG-3100 questions about network layout

    Scheduled Pinned Locked Moved Problems Installing or Upgrading pfSense Software
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    • I
      ice_mf_mike
      last edited by

      So i have my network setup like this:  https://i.imgur.com/lcobYBf.png

      I am trying to figure out how to best configure it.  Initially i had it setup where the router had dhcp(192.x) and pfsense did as well(10.X).  It worked briefly, but then stopped to the point where anything on the 10.x could not access the internet after i rebooted the firewall.  I have no idea why that would have been so i had to remove the firewall so i could get some work done.

      So i am thinking about just letting the router hand out IP addresses and just have Pfsense be a firewall(and also use for VPN and snort/suricata).

      Any feedback regarding pros/cons to each setup would be helpful.  Note that i can not put my xfinity router in bridge mode but i do have DMZ setup to forward everything to the port where pfsense is.

      thanks in advance for the potentially noobish questions.
      lcobYBf.png_thumb
      lcobYBf.png

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      • SammyWooS
        SammyWoo
        last edited by

        As u already heard somewhere it's best to put Xfinity in bridge mode, but if you can't, you can't. Are u renting this modem from Comcast? I don't see why they would refuse to furnish you with a plain modem, but I digress.

        You are doing double-NAT but that's OK. It "should" work, I don't know why it doesn't. Modem's DHCP's affects only the PF's WAN port, it doesn't go beyond that, and the PF's DHCP services your LAN.

        Very simple:

        PF –> Diagnostic --> ping 8.8.8.8, if successful response then PF is able to "get out."

        From any client, do IPCONFIG /ALL, I assume Windows, and GATEWAY === (should) === PF LAN IP.  If this is blank or something else, you have configured PF DHCP wrong.

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        • johnpozJ
          johnpoz LAYER 8 Global Moderator
          last edited by

          comcast -  just buy your own modem and screw renting from them.  I would look at your drawing but its not attached.  And work blocks that url..

          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 2.8, 24.11

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          • I
            ice_mf_mike
            last edited by

            @SammyWoo:

            As u already heard somewhere it's best to put Xfinity in bridge mode, but if you can't, you can't. Are u renting this modem from Comcast? I don't see why they would refuse to furnish you with a plain modem, but I digress.

            You are doing double-NAT but that's OK. It "should" work, I don't know why it doesn't. Modem's DHCP's affects only the PF's WAN port, it doesn't go beyond that, and the PF's DHCP services your LAN.

            Very simple:

            PF –> Diagnostic --> ping 8.8.8.8, if successful response then PF is able to "get out."

            From any client, do IPCONFIG /ALL, I assume Windows, and GATEWAY === (should) === PF LAN IP.  If this is blank or something else, you have configured PF DHCP wrong.

            Thanks.  Let me check this.  Let me ask this.  I was playing with the LAN interface.  Should the IP be /24 or /32?  Whatever i changed it was working and then upon a reboot, DHCP worked but no internet connection.  If it persists ill provide the errors.

            ETA:  i cant use bridge mode because i use their security system which doesnt work in bridge mode.  yea.  its annoying and i am ditching it soon but cant yet.

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            • I
              ice_mf_mike
              last edited by

              @johnpoz:

              comcast -  just buy your own modem and screw renting from them.  I would look at your drawing but its not attached.  And work blocks that url..

              Attachment added.  see above but bridge mode isnt an options as of right now.

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              • SammyWooS
                SammyWoo
                last edited by

                @ice_mf_mike:

                I was playing with the LAN interface.  Should the IP be /24 or /32?

                There is no such thing as /32.  /24 at the PF's LAN interface would be standard, allowing 255 clients.

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                • I
                  ice_mf_mike
                  last edited by

                  Ok.  So i ended up going into console and reverting the configuration basically to the out of the box config.

                  Lets say my router is 192.168.1.1/24
                  Pfsense is 192.168.1.234
                  Pfsense Lan network is 10.0.1.1/24

                  What should i configure the default gateway on the Wan/Lan interfaces?  This is what threw me off last time and rendered my gui useless.

                  Also, should i consider not doing double NAT and just disabling DHCP on pfsense and just using it as a firewall/VPN?

                  Thanks.

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                  • G
                    gsmornot
                    last edited by

                    @SammyWoo:

                    @ice_mf_mike:

                    I was playing with the LAN interface.  Should the IP be /24 or /32?

                    There is no such thing as /32.  /24 at the PF's LAN interface would be standard, allowing 255 clients.

                    /32 is a single address. Mask of 255.255.255.255.

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                    • SammyWooS
                      SammyWoo
                      last edited by

                      If you leave both DHCP handle it, things should be automatic.

                      Gateway is the "upstream" device IP.  So  Router –-> FW ----> Client.  FW Gateway is Router, Client Gateway is FW.

                      Am not aware you can use PF as a FW without it doing NAT, maybe somebody here will jump in and correct me.

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                      • DerelictD
                        Derelict LAYER 8 Netgate
                        last edited by

                        You don't need to do NAT. But in the described case it is probably necessary.

                        But in most cases you would want to do a 1:1 NAT (usually erroneously called a DMZ host or something, which is maddeningly stupid but that's the industry today) in the upstream router to pfSense WAN so all inbound traffic is sent to the WAN port with no further rules require. Then you would port forward as normal on the pfSense WAN.

                        You probably need to outbound NAT as well because the upstream router won't know about routing to the LAN behind pfSense WAN.

                        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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                        • I
                          ice_mf_mike
                          last edited by

                          @SammyWoo:

                          If you leave both DHCP handle it, things should be automatic.

                          Gateway is the "upstream" device IP.  So  Router –-> FW ----> Client.  FW Gateway is Router, Client Gateway is FW.

                          Am not aware you can use PF as a FW without it doing NAT, maybe somebody here will jump in and correct me.

                          Thanks.  When i tried this i was getting a message saying that the gateway was not on the same subnet.  In this example, the Lan interface had say a 10.0.1.1 IP and the router had a 192.168.1.1 IP.  Am i doing it wrong?

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                          • I
                            ice_mf_mike
                            last edited by

                            @Derelict:

                            You don't need to do NAT. But in the described case it is probably necessary.

                            But in most cases you would want to do a 1:1 NAT (usually erroneously called a DMZ host or something, which is maddeningly stupid but that's the industry today) in the upstream router to pfSense WAN so all inbound traffic is sent to the WAN port with no further rules require. Then you would port forward as normal on the pfSense WAN.

                            You probably need to outbound NAT as well because the upstream router won't know about routing to the LAN behind pfSense WAN.

                            Hmm thanks.  I was wondering what 1:1 NAT setting was.  So basically, that setting just forwards all traffic to the LAN or WAN ports.  I think my router has a similar DMZ setting that was planning to use on the port where the FW is plugged in.

                            Maybe this was the reason in my first config that i lost internet access even though the networks were properly NAT'd and DHCP working?

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                            • DerelictD
                              Derelict LAYER 8 Netgate
                              last edited by

                              That setting takes all unsolicited traffic coming into its WAN and forwards it to a specific IP address on the inside. That would be pfSense's WAN address.

                              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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