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    Automatically routed to ISP router Private IP if a client VPN is active

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    • G
      giuliolinux
      last edited by

      Hi, I have about seventy devices configured with Pfsense. The anomaly found is that even if the provider provides us with Public IPs - but his device has a private IP - we are routed to that IP (ex: 192.168.1.1/24) from the WAN interface and the VPN client. As regards the WAN interface, access from pfsense and from internal networks can be blocked (rule with RFC1918 active on the WAN IF), while for the VPN client it is not possible to use these rules on the interface as I must be able to set up the networks of our laboratory to various internet networks corresponding to RFC1918.

      A couple of questions arise:

      1. why and through which protocol does the WAN (or the OpenVPN client) communicate with a private IP of the provider's router if present, even though no PfSense interface has an IP on that net? (ex: 192.168.1.0/24).

      2. What would be the "cleanest" solution to solve this problem given that regardless of the private IP of the provider's router, there is a route to that destination?

      Thank you in advance!

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      • V
        viragomann
        last edited by

        @giuliolinux said in Automatically routed to ISP router Private IP if a client VPN is active:

        A couple of questions arise:

        why and through which protocol does the WAN (or the OpenVPN client) communicate with a private IP of the provider's router if present, even though no PfSense interface has an IP on that net? (ex: 192.168.1.0/24).

        I assume, the ISP router is the default gateway on pfSense. So pfSense routes any destination IPs to it, which it has no other route for.

        What would be the "cleanest" solution to solve this problem given that regardless of the private IP of the provider's router, there is a route to that destination?

        The "cleanest" way would be to assign an IP within the routers subnet to the WAN interface and add an outbound NAT rule for the destination IP of the routers and set it to "no NAT". But obviously this is not really necessary for your ISP router, since it also works with the WAN IP.

        Anyway you have to add the route for the IP to the OpenVPN settings. In the OpenVPN server you can add its IP in CIDR notation to the "Local Networks" to push the route to the clients.
        This cannot be done regardless the the routers IP of course, and why will you have it this way?

        Also you might have to add an outbound NAT rule for the source of the OpenVPN tunnel network and set the translation to "WAN address".

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        • G
          giuliolinux @viragomann
          last edited by

          @viragomann said in Automatically routed to ISP router Private IP if a client VPN is active:

          @giuliolinux said in Automatically routed to ISP router Private IP if a client VPN is active:

          I assume, the ISP router is the default gateway on pfSense. So pfSense routes any destination IPs to it, which it has no other route for.

          yeah, sure...

          The "cleanest" way would be to assign an IP within the routers subnet to the WAN interface and add an outbound NAT rule for the destination IP of the routers and set it to "no NAT". But obviously this is not really necessary for your ISP router, since it also works with the WAN IP.

          Anyway you have to add the route for the IP to the OpenVPN settings. In the OpenVPN server you can add its IP in CIDR notation to the "Local Networks" to push the route to the clients.
          This cannot be done regardless the the routers IP of course, and why will you have it this way?

          Also you might have to add an outbound NAT rule for the source of the OpenVPN tunnel network and set the translation to "WAN address".

          OK, I will try. I will also try asking the provider to exclude this route from their router / default gateway.

          Many thanks for your support and your time!

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          • V
            viragomann @giuliolinux
            last edited by

            @giuliolinux said in Automatically routed to ISP router Private IP if a client VPN is active:

            I will also try asking the provider to exclude this route from their router / default gateway.

            Which route do you mean?

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            • G
              giuliolinux @viragomann
              last edited by

              @viragomann

              ... I mean to remove the 192.168.1.0/24 from their routes on the perimetral router of the ISP.

              Regards

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              • V
                viragomann @giuliolinux
                last edited by

                @giuliolinux
                The router has an IP in the 192.168.1.0/24 subnet, and hence he also has a route for this.
                The IP is meant to give you access to it. Without the route that won't be possible.

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                • G
                  giuliolinux @viragomann
                  last edited by

                  @viragomann

                  Hi,

                  I think there is a misunderstanding. Our WAN has a default gateway on a public subnet. This link allows us to apply virtual IPs on pfsense to manage the 64 Public IPs that the ISP provides us and then the various internal networks are routed externally via the outbound specifications that use some of the 64 Public IPs. None of our internal networks use the 192.168.1.0/24 subnet, and these routes are not present even in the VPNs we establish to our customers' destinations. So I assume that the public route on the ISP's p2p routes us to its device (basically we have no hops with a traceroute) ...

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                  • G
                    giuliolinux @giuliolinux
                    last edited by

                    @giuliolinux

                    ... I mean no hops to 192.168.1.1.

                    Regards

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                    • V
                      viragomann @giuliolinux
                      last edited by

                      @giuliolinux
                      It's the next device to WAN directly linked to pfSense. I don't expect to see a hop to this IP.

                      And there might also be no route.
                      I assume the ISP router as a public IP as well and this is used on pfSense as upstream gateway.
                      So since your pfSense doesn't know any other route for 192.168.1.1, it will send requests to this destination to the gateway IP, which is the same device. So the router will respond to that.

                      Same on your pfSense. You say, you have multiple internal networks. So you can go to a device in subnet A and call the subnet B IP of pfSense. Presumed the firewall rules on A allows it, pfSense will respond normally.

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                      • G
                        giuliolinux @viragomann
                        last edited by

                        @viragomann

                        Hi,

                        I try to explain better below. Configuring our WAN:

                        WAN address (point to point of the ISP):

                        IP: 89.2**.2**.78
                        Def-GW: 89.2**.2**.77

                        As I wrote above through the ISP's p2p connection we can use 64 IPs (Virtual IPs with Proxy Arp). This allows us to set outbound and inbound access to services. Let's say that I will describe this last aspect to you but it is not important in the evaluation of the subject matter.

                        Pfsense routing - as shown below - means that there is no interface set up on the 192.168.1.1 network (it is an ISP device since we only hop from pfsense to that IP).

                        default 89.2**.2**.77 UGS 686922 1500 bce1
                        1.0.0.1 10.128.0.1 UGHS 10625481 1500 em3
                        1.1.1.1 89.212.25.77 UGHS 10624184 1500 bce1
                        8.8.8.8 77.94.136.193 UGHS 10624818 1500 bce0
                        10.0.0.0/24 10.10.82.1 UGS 1 1500 ovpnc35
                        10.0.1.0/28 link#11 U 24068685 1500 em2.100
                        10.0.1.14 link#11 UHS 0 16384 lo0
                        10.0.1.16/28 link#12 U 24371836 1500 em2.101
                        10.0.1.30 link#12 UHS 0 16384 lo0
                        10.0.1.32/28 link#13 U 0 1500 em2.102
                        10.0.1.46 link#13 UHS 0 16384 lo0
                        10.0.1.48/28 link#14 U 0 1500 em2.103
                        10.0.1.62 link#14 UHS 0 16384 lo0
                        10.0.1.64/28 link#15 U 14864827 1500 em2.104
                        10.0.1.78 link#15 UHS 0 16384 lo0
                        10.0.1.80/28 link#16 U 87763530 1500 em2.105
                        10.0.1.94 link#16 UHS 0 16384 lo0
                        10.0.1.96/28 link#17 U 0 1500 em2.106
                        10.0.1.110 link#17 UHS 0 16384 lo0
                        10.0.1.112/28 link#18 U 0 1500 em2.107
                        10.0.1.126 link#18 UHS 0 16384 lo0
                        10.0.1.128/28 link#19 U 13693489 1500 em2.108
                        10.0.1.142 link#19 UHS 0 16384 lo0
                        10.0.1.144/28 link#20 U 747606 1500 em2.109
                        10.0.1.158 link#20 UHS 0 16384 lo0
                        10.0.1.160/28 link#21 U 15640132 1500 em2.110
                        10.0.1.174 link#21 UHS 0 16384 lo0
                        10.0.1.176/28 link#22 U 10033377 1500 em2.111
                        10.0.1.190 link#22 UHS 0 16384 lo0
                        10.0.1.192/28 link#23 U 11 1500 em2.112
                        10.0.1.206 link#23 UHS 0 16384 lo0
                        10.0.1.208/28 link#24 U 0 1500 em2.113
                        10.0.1.222 link#24 UHS 0 16384 lo0
                        10.0.1.224/28 link#25 U 0 1500 em2.114
                        10.0.1.238 link#25 UHS 0 16384 lo0
                        10.0.1.240/28 link#26 U 0 1500 em2.115
                        10.0.1.254 link#26 UHS 0 16384 lo0
                        10.0.2.0/28 link#27 U 0 1500 em2.116
                        10.0.2.14 link#27 UHS 0 16384 lo0
                        10.0.2.16/28 link#28 U 0 1500 em2.117
                        10.0.2.30 link#28 UHS 0 16384 lo0
                        10.0.2.32/28 link#29 U 0 1500 em2.118
                        10.0.2.46 link#29 UHS 0 16384 lo0
                        10.0.2.48/28 link#30 U 0 1500 em2.119
                        10.0.2.62 link#30 UHS 0 16384 lo0
                        10.0.2.64/28 link#31 U 0 1500 em2.120
                        10.0.2.78 link#31 UHS 0 16384 lo0
                        10.0.2.80/28 link#32 U 0 1500 em2.121
                        10.0.2.94 link#32 UHS 0 16384 lo0
                        10.0.2.96/28 link#33 U 0 1500 em2.122
                        10.0.2.110 link#33 UHS 0 16384 lo0
                        10.0.2.112/28 link#34 U 0 1500 em2.123
                        10.0.2.126 link#34 UHS 0 16384 lo0
                        10.0.2.128/28 link#35 U 0 1500 em2.124
                        10.0.2.142 link#35 UHS 0 16384 lo0
                        10.0.2.144/28 link#36 U 0 1500 em2.125
                        10.0.2.158 link#36 UHS 0 16384 lo0
                        10.0.2.160/28 link#37 U 0 1500 em2.126
                        10.0.2.174 link#37 UHS 0 16384 lo0
                        10.0.2.176/28 link#38 U 0 1500 em2.127
                        10.0.2.190 link#38 UHS 0 16384 lo0
                        10.0.2.192/28 link#39 U 0 1500 em2.128
                        10.0.2.206 link#39 UHS 0 16384 lo0
                        10.0.2.208/28 link#40 U 0 1500 em2.129
                        10.0.2.222 link#40 UHS 0 16384 lo0
                        10.0.2.224/28 link#41 U 0 1500 em2.130
                        10.0.2.238 link#41 UHS 0 16384 lo0
                        10.0.2.240/28 link#42 U 0 1500 em2.131
                        10.0.2.254 link#42 UHS 0 16384 lo0
                        10.0.3.0/29 link#43 U 3877802 1500 em2.132
                        10.0.3.6 link#43 UHS 0 16384 lo0
                        10.0.3.8/29 link#44 U 3939412 1500 em2.133
                        10.0.3.14 link#44 UHS 0 16384 lo0
                        10.0.3.16/29 link#45 U 15005758 1500 em2.134
                        10.0.3.22 link#45 UHS 0 16384 lo0
                        10.0.3.24/29 link#46 U 325012 1500 em2.135
                        10.0.3.30 link#46 UHS 0 16384 lo0
                        10.0.3.32/29 link#47 U 4456046 1500 em2.136
                        10.0.3.38 link#47 UHS 0 16384 lo0
                        10.0.3.40/29 link#48 U 2932343 1500 em2.137
                        10.0.3.46 link#48 UHS 0 16384 lo0
                        10.0.3.48/29 link#49 U 2125567 1500 em2.138
                        10.0.3.54 link#49 UHS 0 16384 lo0
                        10.0.3.56/29 link#50 U 1633429 1500 em2.139
                        10.0.3.62 link#50 UHS 0 16384 lo0
                        10.0.3.64/29 link#51 U 1556704 1500 em2.140
                        10.0.3.70 link#51 UHS 0 16384 lo0
                        10.0.3.72/29 link#52 U 792059 1500 em2.141
                        10.0.3.78 link#52 UHS 0 16384 lo0
                        10.0.3.80/29 link#53 U 1133122 1500 em2.142
                        10.0.3.86 link#53 UHS 0 16384 lo0
                        10.0.3.88/29 link#54 U 0 1500 em2.143
                        10.0.3.94 link#54 UHS 0 16384 lo0
                        10.0.3.96/29 link#55 U 2615458 1500 em2.144
                        10.0.3.102 link#55 UHS 0 16384 lo0
                        10.0.3.104/29 link#56 U 0 1500 em2.145
                        10.0.3.110 link#56 UHS 0 16384 lo0
                        10.0.3.112/29 link#57 U 0 1500 em2.146
                        10.0.3.118 link#57 UHS 0 16384 lo0
                        10.0.3.120/29 link#58 U 0 1500 em2.147

                        Thanks for your help.

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                        • G
                          giuliolinux @viragomann
                          last edited by

                          @viragomann

                          yesss, all clear. My problem is that I have a new customer that have a LAN network 192.168.1.0/24 that I will have to reach from Pfsense - and our networks above -

                          So I hope that the ISP router does not intercept them, but that I will reach that network via Ovpn Client.

                          Regards

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                          • V
                            viragomann @giuliolinux
                            last edited by

                            @giuliolinux said in Automatically routed to ISP router Private IP if a client VPN is active:

                            My problem is that I have a new customer that have a LAN network 192.168.1.0/24 that I will have to reach from Pfsense

                            That's the thing I was missing before.

                            I guess, the customer is connected via an OpenVPN site-to-site. So add 192.168.1.0/24 to the "Remote Networks" in your pfSense VPN settings.

                            There is nothing, the ISP can do for achieve access to this customer.
                            As said, if pfSense has no other route it directs destination IPs to the default gateway.

                            G 1 Reply Last reply Reply Quote 0
                            • G
                              giuliolinux @viragomann
                              last edited by

                              @viragomann

                              Ok,

                              thanks for your precious help, and in any case sorry for my approx english ;P

                              Ciao (form Italy)

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