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    [SOLVED] Problem Vlan Trunk with cisco switch

    Scheduled Pinned Locked Moved General pfSense Questions
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    • JKnottJ
      JKnott
      last edited by

      If you're using native LAN between the switch & pfSense, you will need an address on the native LAN in pfSense.  Or don't make VLAN 100 native on the connection.  Your choice.

      As I said, use Wireshark, so that you can see exactly what's happening.  PfSense does have Packet Capture, but I find Wireshark is much more useful.

      PfSense running on Qotom mini PC
      i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
      UniFi AC-Lite access point

      I haven't lost my mind. It's around here...somewhere...

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      • O
        omarmohammed
        last edited by

        i have set up an interface for the vlan 1 which is the native vlan with the ip add 10.4.30.1/24 in pfsense

        when i use wireshark start capture in the link between pfsense and the switch and then try a ping to the pfsense subinterface 10.4.10.1 with the pc (10.4.10.2) i get nothing and also when i use the same thing with the router even the ping get through i see no wireshark packet it might not be working

        The différence in the mac address tables that i said in the previous post might help… i dont know

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        • JKnottJ
          JKnott
          last edited by

          If you're seeing nothing on the link to pfSense, then your problem is within the switch.  If it was configured properly, you should see the ping encapsulated in a VLAN tagged frame.

          PfSense running on Qotom mini PC
          i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
          UniFi AC-Lite access point

          I haven't lost my mind. It's around here...somewhere...

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          • O
            omarmohammed
            last edited by

            i think my wireshark doesnt work properly because even when i change pfsense with the configured router the ping works but still nothing when trying to get packet capture with wireshark

            in pfsense with packet log when i ping i can only see an arp request and an arp response that's all

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            • JKnottJ
              JKnott
              last edited by

              @omarmohammed:

              i think my wireshark doesnt work properly because even when i change pfsense with the configured router the ping works but still nothing when trying to get packet capture with wireshark

              in pfsense with packet log when i ping i can only see an arp request and an arp response that's all

              Have you set up a mirror port on the switch?  A mirror port is one that copies traffic from another.  This is the only way a switch can be used to monitor traffic.  A while ago, I bought a small, cheap managed switch, to be used just for this purpose.  You connect a computer running Wireshark to the mirror port.  You can use Packet Capture, in pfSense, but it's limited in what it can do and it's often necessary to download the capture and read it with Wireshark.

              As for arp, all that does is map an IP address to the MAC address.  What IP address does it show?  Is it one you expect?

              PfSense running on Qotom mini PC
              i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
              UniFi AC-Lite access point

              I haven't lost my mind. It's around here...somewhere...

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              • A
                AndrewZ
                last edited by

                @JKnott:

                PfSense does have Packet Capture, but I find Wireshark is much more useful.

                Just want to mention that it is possible to use tcpdump from the shell with '-e' to see VLAN tags.
                Agree that mirror port gives some benefits, but for quick check on pfSense trunk port tcpdump will do the job perfectly. Just my 2¢.

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                • JKnottJ
                  JKnott
                  last edited by

                  One nice feature of Wireshark is you can use both capture and display filters.

                  PfSense running on Qotom mini PC
                  i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
                  UniFi AC-Lite access point

                  I haven't lost my mind. It's around here...somewhere...

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                  • O
                    omarmohammed
                    last edited by

                    I FINALLY MANAGED to make wireshark work (update, change npcap with winpcap, update gns3…)

                    here is the capture attached between the switch and pfsense, i really dont get why i didnt get any problem when using a normal router

                    i m really stuck...

                    whenever something is related to a vlan interface in pfsense that doesnt work for me : the parent interface is correctly enabled with no ip, the vlan interface is set with correct ip and mask, the link is correctly set, the firewall rules in the parent and vlan interfaces are set to allow anything

                    is the VTP domain the problem ? i have also set VTP mode to transparent

                    [Between pfsense and switch.pcapng](/public/imported_attachments/1/Between pfsense and switch.pcapng)
                    [between switch and end router.pcapng](/public/imported_attachments/1/between switch and end router.pcapng)

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                    • JKnottJ
                      JKnott
                      last edited by

                      I've just looked at the switch - pfsense capture.  All I see is arp requests, on VLAN 20, from 10.4.20.2 to 10.4.20.1, but no replies along with some CDP (irrelevant) and LOOP.  What is the LOOP doing there?  If you run Packet Capture on opt4 (VLAN 20), do you see the arp requests from 10.4.20.2?  Do you see them on any interface?  Also, according to your diagram, the PC traffic should be on VLAN 10 between the switch and pfSense.  Why are those arp requests on VLAN 20?

                      On switch - router, I see those arp requests from 10.4.20.2 on native LAN.  What are they doing there?  I thought traffic to the router should be on VLAN 20 at that point.

                      It looks like you haven't got the switch configured properly.

                      PfSense running on Qotom mini PC
                      i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
                      UniFi AC-Lite access point

                      I haven't lost my mind. It's around here...somewhere...

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                      • O
                        omarmohammed
                        last edited by

                        i just want to make work one of them so i put  the start capture between pfsense and switch, then switch and end router which is the end device showed at the bottom right.

                        i dont know why the loop is there

                        the interface of the router is on vlan 20, the one with the pc is on vlan 10.

                        as for the int giga 0/1 connected to the router is correctly configured : switchport mode access, and switchport access vlan 20

                        for the giga 0/0 connected to pfsense : switchport mode trunk, switchport trunk encapsulation dot1q

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                        • JKnottJ
                          JKnott
                          last edited by

                          the interface of the router is on vlan 20, the one with the pc is on vlan 10.

                          Yet the capture shows the arp request on VLAN 20.  That tells me the port you think is on VLAN 10 is actually on 20.

                          as for the int giga 0/1 connected to the router is correctly configured : switchport mode access, and switchport access vlan 20

                          Then why does the arp request for 10.4.20.1 appear on the native LAN going to the router?  Isn't that a different subnet from the PC?  Arp is a broadcast and routers don't normally pass broadcasts.

                          If I'm not mistaken, the PC is on 10.4.10.0 /24 & VLAN 10 between the switch and pfsense.  The router is on 10.4.20.0 /24 and on VLAN 20 between the switch & pfsense.

                          Since those are separate subnets, packets from the PC should not appear at the router, unless forwarded by pfSense.  Yet, the PC pfSense link shows arp from the PC on VLAN20 to pfSense and then appearing on the router native LAN, with the same MAC address.  This proves that you've got both switch ports on the same VLAN.  Even with routed packets, the MAC address should contain the MAC from the pfSense interface.  Arp packets shouldn't make it between the 2 VLANs at all.

                          PfSense running on Qotom mini PC
                          i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
                          UniFi AC-Lite access point

                          I haven't lost my mind. It's around here...somewhere...

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                          • O
                            omarmohammed
                            last edited by

                            I assure you that :

                            int giga 0/1 (connected to pc) is switchport mode access vlan 10
                            int giga 0/2 (connected to end router) is switchport mode access vlan 20

                            i see that its normally done when i do a sho int status

                            and int giga 0/0 (connected to pfsense) is trunk with encapsulation dot1Q

                            i changed the switch with a new switch with another config type and everything, configured it, and made it work with router (in the place of pfsense), then tried with pfsense, still not working

                            router
                                        |
                                      switch
                                    /         
                                  PC        end router

                            this is working, but with pfsense its not :

                            pfsense
                                        |
                                      switch
                                    /         
                                  PC        end router

                            here i attached the new wireshark files, this time i see the icmp going in vlan 20 to the pfsense, then the problem is in pfsense i think… (no response)

                            i see there no arp

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                            • O
                              omarmohammed
                              last edited by

                              Just so you know the pc is not started, i work with the router, because if it works for the end router in vlan 20, it will work for the pc.

                              [Between pfsense and new switch.pcapng](/public/imported_attachments/1/Between pfsense and new switch.pcapng)
                              [between end router (bottom right) and new switch.pcapng](/public/imported_attachments/1/between end router (bottom right) and new switch.pcapng)

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                              • JKnottJ
                                JKnott
                                last edited by

                                @omarmohammed:

                                Just so you know the pc is not started, i work with the router, because if it works for the end router in vlan 20, it will work for the pc.

                                Then where is that arp request coming from?  If you want help, you need to accurately describe the network.  We can't just assume what you think is correct.

                                PfSense running on Qotom mini PC
                                i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
                                UniFi AC-Lite access point

                                I haven't lost my mind. It's around here...somewhere...

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                                • O
                                  omarmohammed
                                  last edited by

                                  the arps are coming from the end router look at the ip adresses it's 10.4.20.1(int VLAN20) and 10.4.20.2(end router) it's you who is confused where do you see an arp coming from the pc

                                  in the mac addr table in this new switch with pfsense, i dont have mac addr from the pfsense int with any vlan, just the one with the router

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                                  • O
                                    omarmohammed
                                    last edited by

                                    Do i need a static route from pfsense to switch ??? the switch is only a layer 2 switch, it cannot manage to make it work ???

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                                    • O
                                      omarmohammed
                                      last edited by

                                      when trying to ping from pfsense, there are no arp replies : the router doesnt reply to pfsense ! and this reply is shown on the other side !

                                      My guess is that the switch doesnt let throught this arp, even his mac address is not showing pfsense mac address interface

                                      OK WHEN activating ip cef command in the switch those arp begin to pass ! now, i get only vlan 1 behind the mac address of pfsense, still no vlan 10 or 20 even thought the ping starts from the end router and the port connected to it is in vlan 20

                                      OK i added statically the mac address in the switch, and the arp entry in the end router, the ping request goes throught, the ping response stops at the switch, AND ALSO THE PING REQUEST IS TAGGED VLAN 20 but the ping response is not tagged !!

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                                      • DerelictD
                                        Derelict LAYER 8 Netgate
                                        last edited by

                                        Post a screen shot of the pfSense Interfaces > Assignments screen

                                        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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                                        • JKnottJ
                                          JKnott
                                          last edited by

                                          the arps are coming from the end router look at the ip adresses it's 10.4.20.1(int VLAN20) and 10.4.20.2(end router) it's you who is confused where do you see an arp coming from the pc

                                          In your first post, you say:

                                          the PC has as ip addr: 10.4.10.2

                                          Maybe I'm confused because I read what you wrote.

                                          Do i need a static route from pfsense to switch ??? the switch is only a layer 2 switch, it cannot manage to make it work ???

                                          You don't route to switches.  You route to IP networks.  Switches are transparent, forwarding only on MAC addresses.

                                          My guess is that the switch doesnt let throught this arp, even his mac address is not showing pfsense mac address interface

                                          Nonsense.  Switches pass Ethernet frames, no matter what they're carrying.

                                          AND ALSO THE PING REQUEST IS TAGGED VLAN 20 but the ping response is not tagged !!

                                          I mentioned that in an earlier reply.  You've got a configuration error somewhere.  I'd suspect the switch.

                                          PfSense running on Qotom mini PC
                                          i5 CPU, 4 GB memory, 32 GB SSD & 4 Intel Gb Ethernet ports.
                                          UniFi AC-Lite access point

                                          I haven't lost my mind. It's around here...somewhere...

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                                          • O
                                            omarmohammed
                                            last edited by

                                            here is the assignements screen attached

                                            to answer you JKnott 10.4.10.2 is not in the 10.4.20.0/24 subnet and there are NO ARP with the PC address in the wiresharks i provided that's why i dont know what you're talking about

                                            the switch conf also attached if you want, but i doubt that since its working with the router

                                            ![Sans titre.png](/public/imported_attachments/1/Sans titre.png)
                                            ![Sans titre.png_thumb](/public/imported_attachments/1/Sans titre.png_thumb)
                                            ![Sans titre1.png](/public/imported_attachments/1/Sans titre1.png)
                                            ![Sans titre1.png_thumb](/public/imported_attachments/1/Sans titre1.png_thumb)
                                            ![Sans titre2.png](/public/imported_attachments/1/Sans titre2.png)
                                            ![Sans titre2.png_thumb](/public/imported_attachments/1/Sans titre2.png_thumb)

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