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    Routing between Networks behind different WAN IPs

    Scheduled Pinned Locked Moved General pfSense Questions
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    • D Offline
      dabbelju007
      last edited by

      Sorry for being not clear in my description. Everything described is connected to one pfSense. I did try to draw it down.

      The green way is working. the red way is not.

      scenario.jpg

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      • V Offline
        viragomann @dabbelju007
        last edited by

        @dabbelju007
        I assumed that as mentioned above.

        So either add a DNS host override, when using a hostname to access the server or enable NAT reflection.

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        • johnpozJ Offline
          johnpoz LAYER 8 Global Moderator
          last edited by johnpoz

          If you policy route, ie send traffic from lan2 out wan2.. There has to be a rule above that in lan2 rules that allows it to get to lan1..

          Its all in the multwan doc
          https://docs.netgate.com/pfsense/en/latest/multiwan/policy-route.html

          See the Bypassing Policy Routing section.

          The red way is not how you would do it.. this is the way it would be done.

          lan1-2.png

          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 25.07 | Lab VMs 2.8, 25.07

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          • D Offline
            dabbelju007
            last edited by

            @viragomann Thanks for your advice.

            Just for a test: Rule at LAN2 allows IPv4 any protocol to any destination. I am using IPv4 addresses.

            The NAT Port Forward Rule @WAN1 Interface has NAT refelction enabled, as you said pure NAT.

            It is still not working.

            I know the Firewall Log, State Log and packet capture. Is there a way in pfSense to see in which steps this reuqest is handeled?

            When I do the request and take a look into the firewall log I can see that there is an entry which "allows the request" out from LAN2. There is no entry for the NAT rule @WAN1 (logging in the rules is enabled).

            What do I do wrong?

            Thanks
            Dabbelju

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            • V Offline
              viragomann @dabbelju007
              last edited by

              @dabbelju007
              Are you able to access the server by its internal IP?

              You can sniff the packets on LAN1 using Diagnotic > Packet Capture.
              When trying to access from LAN2 you should see the packets here else well as the responds from the server.

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              • D Offline
                dabbelju007
                last edited by

                @viragomann
                I have access to the server. If I take captures at all four interfaces (LAN2, WAN2, WAN1, LAN1) I do only see the request leaving LAN2 and nothing at the other captures.

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                • johnpozJ Offline
                  johnpoz LAYER 8 Global Moderator
                  last edited by

                  @dabbelju007 said in Routing between Networks behind different WAN IPs:

                  I do not want to allow traffic from LAN2 to LAN1 directly.

                  Why?? For what possible reason would you not just let lan2 talk to lan1 via your rule? Sending traffic out wan2 just to come in wan 1 gets you nothing other than non optimal traffic flow.

                  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 25.07 | Lab VMs 2.8, 25.07

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                  • V Offline
                    viragomann
                    last edited by

                    So you can access the server by its IP, but not via the WAN address.

                    @dabbelju007 said in Routing between Networks behind different WAN IPs:

                    If I take captures at all four interfaces (LAN2, WAN2, WAN1, LAN1) I do only see the request leaving LAN2 and nothing at the other captures.

                    As @johnpoz illustrated, the connection doesn't pass the WANs, so you cannot see the packets there.
                    On LAN2 you only see request packets to WAN1 and nothing else?
                    So the NAT reflection is probably not working.

                    Do you use a hostname for accessing from outside. If, you can add a host override.

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                    • D Offline
                      dabbelju007 @johnpoz
                      last edited by

                      @johnpoz

                      Thats whats I will do. I thought it must be possible the other way even if I produce unnecessary traffic.

                      But how can I use the public IP of WAN1 from LAN2 even if I route it directly? Would that be makeable by another NAT rule?

                      Background to my question is that I have users using the service from home. Sometimes they come into our office and are connected to LAN2 and want to use the same service.

                      Ok, if I would use DNS names I would know a way. But is it possible by using the public IP and a NAT Rule?

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                      • V Offline
                        viragomann @dabbelju007
                        last edited by

                        @dabbelju007 said in Routing between Networks behind different WAN IPs:

                        Would that be makeable by another NAT rule?

                        That's what NAT reflection should do for you automatically. It implies an invisible NAT rule.

                        But yeah, you may as well add a NAT rule manuelly to LAN2 if you want that.
                        source: WAN1 address
                        dest: server

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                        • johnpozJ Offline
                          johnpoz LAYER 8 Global Moderator
                          last edited by johnpoz

                          Local dns resolution is the whole point of split dns. When the is on some other network they would use the public IP and access via your port forward.

                          When they are on the site where the server is - the dns on the site would point the them to the local IP.

                          Where you run into a problem is if the client is not using your dns when they come to your site. And only resolve the public IP. This is where nat reflection would come into play. But the use of dual wan would complicate the use of nat reflection most likely. This should only be an issue if they were hard coding their dns vs using dhcp to get their dns, or they were using doh in their browsers, etc.

                          You could do maybe just a redirection on your lan 2 interface - if traffic hits lan 2 going to your wan 1 public 1.2.3.4 on port X, you just port forward that to server IP..

                          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 25.07 | Lab VMs 2.8, 25.07

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                          • stephenw10S Online
                            stephenw10 Netgate Administrator
                            last edited by

                            I would probably just use NAT reflection here if the requirement is only occasional.

                            https://docs.netgate.com/pfsense/en/latest/recipes/port-forwards-from-local-networks.html#method-1-nat-reflection

                            Adding a bunch of custom rules is only going to cause you more maintenance time at some point in the future.

                            Steve

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                            • V Offline
                              viragomann
                              last edited by

                              However, due to the Multi-WAN setup, maybe you need the NAT reflection with proxy mode.

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                              • stephenw10S Online
                                stephenw10 Netgate Administrator
                                last edited by

                                I would expect Pure NAT to work. You wouldn't even need the auto-outbound rules since it's between two different internal interfaces. I would enable them anyway though to allow access fro the same interface if it's ever required.

                                Steve

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                                • V Offline
                                  viragomann @stephenw10
                                  last edited by

                                  @stephenw10
                                  The strange thing, as the TO mentioned, he can access the server by its internal IP, but not by the WAN IP with NAT reflection in pure NAT mode.
                                  So the rules must be okay, but the NAT reflection seems not to work.

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                                  • stephenw10S Online
                                    stephenw10 Netgate Administrator
                                    last edited by

                                    I don't actually see anywhere he said he enabled NAT reflection. I just see everyone suggesting it...

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                                    • D Offline
                                      dabbelju007 @dabbelju007
                                      last edited by

                                      @dabbelju007 said in Routing between Networks behind different WAN IPs:

                                      @viragomann Thanks for your advice.

                                      Just for a test: Rule at LAN2 allows IPv4 any protocol to any destination. I am using IPv4 addresses.

                                      The NAT Port Forward Rule @WAN1 Interface has NAT refelction enabled, as you said pure NAT.

                                      It is still not working.

                                      I know the Firewall Log, State Log and packet capture. Is there a way in pfSense to see in which steps this reuqest is handeled?

                                      When I do the request and take a look into the firewall log I can see that there is an entry which "allows the request" out from LAN2. There is no entry for the NAT rule @WAN1 (logging in the rules is enabled).

                                      What do I do wrong?

                                      Thanks
                                      Dabbelju

                                      @stephenw10
                                      I did activate it. I will do some further testing today.

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                                      • D Offline
                                        dabbelju007
                                        last edited by dabbelju007

                                        Hi all,

                                        sorry if I start bothering. But I really like pfSense and want to understand as much as possible.

                                        I did do some further testing (NAT Reflection Enabled with "pure NAT" and "NAT + Proxy"). I did enable it under "System=>Advanced=>Firewall & NAT" as well as in the corresponding NAT rule @WAN1.

                                        I did take traces at all involved interfaces (LAN2, WAN2, WAN1, LAN1, Server) in the different scenarios. The only point where I see the packets is @LAN2. Whatever pfSense does I should see it hitting the server which is not the case.

                                        What I currently do not understand: I have enable the NAT reflection at @WAN1 NAT rule. How can NAT reflection do whatever it does when the traffic is not even hitting the Interface? Shouldn't there be a Rule allowing NAT reflection @LAN2 or @WAN2?

                                        Is there any other way to do debugging appart from Traces, Firewall System Logs, State Logs?

                                        I would expect at least to see the packets also @LAN1 or am I wrong?

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                                        • johnpozJ Offline
                                          johnpoz LAYER 8 Global Moderator
                                          last edited by

                                          Nat reflection is not going to work if your policy routing shoving it out a gateway.

                                          If lan2 is trying to hit server in lan1, post up your rules you have on lan2

                                          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 25.07 | Lab VMs 2.8, 25.07

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                                          • stephenw10S Online
                                            stephenw10 Netgate Administrator
                                            last edited by

                                            Yeah, you will need to have a firewall rule allowing traffic from LAN1 to the server in LAN2 to pass the reflected traffic without being routed to any gateway.

                                            With NAT reflection enabled when a client on any internal subnet tries to hit the WAN2 IP on a port that is forwarded it actually hits a NAT rule that sends it to the target directly. Then it hits the firewall so a rule must exist to pass the redirected traffic.

                                            Steve

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