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    PFSense [RST, ACK] packet when accessing a site

    Scheduled Pinned Locked Moved General pfSense Questions
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    • johnpozJ
      johnpoz LAYER 8 Global Moderator @stephenw10
      last edited by

      When you see a RST internally, its almost always going to be the OS of the device your trying to talk to. A firewall like pfsense, normally would never send a RST.. Unless you have a real specific rule setup to "reject" Which you really would rarely want on wan side. Internally such rules can be useful..

      There some special use cases for reject on wan. If you want it to answer for traceroute for example is one that comes to mind. But normally a RST means you talked to OS, or OS firewall.. Since normally a firewall between you and your end device wouldn't send RST for traffic it doesn't allow. Default is normally to just drop traffic that is not allowed.

      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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      • 4
        4o4rh @stephenw10
        last edited by 4o4rh

        @stephenw10 so check "do not NAT"? like below?

        Interface 	Source 	Source Port 	Destination 	Destination Port 	NAT Address 	NAT Port 	Static Port 	Description 	Actions
          	VLAN_2_INTERN 	192.168.2.5/32 	8000 	192.168.4.7/32 	8000 	NO NAT		* 		TEST WEEWX Rule
        
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        • 4
          4o4rh @johnpoz
          last edited by

          @johnpoz thanks to you and steve for the clarification. freenas is freebsd.

          how can i establish what on the box is causing it?
          e.g. ip tables, etc?

          can you offer some commands i could use to validate pls

          johnpozJ 1 Reply Last reply Reply Quote 0
          • johnpozJ
            johnpoz LAYER 8 Global Moderator @4o4rh
            last edited by johnpoz

            No what stephenw10 is talking about is a source nat to get around rules that might stop traffic to a device, where the traffic is from another network.

            server is on vlanX 192.168.1.100 for example, and you want to talk to it from device on vlanY 192.168.2.200 for example.

            If 1.100 does not allow access to its services, because of firewall, or lack of gateway for example. You can do a outbound, or source nat to trick the 1.100 device to think the traffic came from pfsense IP in vlanX, say 192.168.1.1

            This is outbound nat, set on the vlanX interface to set the source of the traffic to pfsense IP address in that interface. Here is example I have setup to talk to 9.101 device on my network because it has no gateway. So to the device when I talk to it from my vpn... It thinks the traffic came from pfsense IP address 9.253

            outboundnat.png

            I would not suggest this, unless the reason you can not talk to the device is no gateway.. You need to adjust the firewall on the device your trying to talk to allow traffic from where your talking from.

            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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            • stephenw10S
              stephenw10 Netgate Administrator
              last edited by

              Yes, that ^.

              But, also yes, you can use that to prove where the problem is but you should fix it at the root which is probably the server config or some rule in the FreeNAS networking.

              Steve

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              • 4
                4o4rh @stephenw10
                last edited by 4o4rh

                @stephenw10 ok, guys. thanks. I can see the port 8000 is coming from the svr vlan gateway address now instead of the wh2900c. and it is still being reset.

                So it is clear, it is the truenas 12.1 box (or the jail that the weewx is running in).

                any chance to guide me here with your freebsd knowledge pls

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                • stephenw10S
                  stephenw10 Netgate Administrator
                  last edited by

                  How exactly are you seeing that? In the state table? Packet capture?

                  I would have expected the connection to succeed after being translated to the interface address.

                  Steve

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                  • 4
                    4o4rh @stephenw10
                    last edited by

                    @stephenw10 packet capture instead of the wh2900c address from before, it shows the svr vlan gateway address. so both addresses are on the same network.

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                    • stephenw10S
                      stephenw10 Netgate Administrator
                      last edited by

                      Mmm, OK. Well if you are seeing traffic leave the interface the server is on and using the interface IP then pfSense is both routing and translating correctly.
                      Something in the FreeNAS firewall or the server config is rejecting it for some other reason.

                      Check the server logs. Are those requests actually getting that far?

                      Steve

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                      • 4
                        4o4rh @stephenw10
                        last edited by

                        @stephenw10 thanks guys. i got it working. was an issue with the application.

                        johnpozJ 1 Reply Last reply Reply Quote 1
                        • johnpozJ
                          johnpoz LAYER 8 Global Moderator @4o4rh
                          last edited by

                          @gwaitsi said in PFSense [RST, ACK] packet when accessing a site:

                          i got it working. was an issue with the application.

                          I would remove your source nat then.. I wouldn't recommend natting between local networks.

                          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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                          • 4
                            4o4rh @johnpoz
                            last edited by

                            @johnpoz already did, thanks :-)

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