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    I can ping PFSense but PFSense can't ping back

    Scheduled Pinned Locked Moved General pfSense Questions
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    • GertjanG
      Gertjan
      last edited by

      Hi,

      LAN interface settings and firewall rules ?

      No "help me" PM's please. Use the forum, the community will thank you.
      Edit : and where are the logs ??

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      • -
        -striker- 0
        last edited by

        Nothing terribly special in either of those as far as I can tell. Screenshots are below. The "US_VPN_Client_IP's" is an alias for IP addresses ranged through 10.0.100.90 - 10.0.100.94. The blocking firewall rule only applies to those IP's to prevent them from accessing the WAN as I only want them to exit PFSense via the VPN tunnel established for them.

        0_1548516416508_LANInterface.JPG

        0_1548516425346_FirewallLANRules.JPG

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        • johnpozJ
          johnpoz LAYER 8 Global Moderator
          last edited by

          well do a sniff on your lan when you do your ping test from pfsense.. Does it send the ping? And is the ping going to the correct mac address?

          Do you have any floating rules?

          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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          • -
            -striker- 0
            last edited by

            I do not have any floating rules defined.

            The MAC address for 10.0.100.51 is: 00:22:15:9f:4b:51 which I see in the sniff results below as the destination of the ping, so the ping is being sent, but it is not reaching the destination or it is not being replied to.

            As I can ping 10.0.100.51 from other machines on the network and receive a response, it seems like the ping is being blocked from leaving PFSense, but i'm not sure how or why that would occur.

            Results from the sniff show:

            09:50:01.664068 00:11:09:d7:2b:fa > 00:22:15:9f:4b:51, ethertype IPv4 (0x0800), length 98: (tos 0x0, ttl 64, id 7165, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->f178)!)
            255.255.255.0 > 10.0.100.51: ICMP echo request, id 16367, seq 0, length 64
            09:50:02.671776 00:11:09:d7:2b:fa > 00:22:15:9f:4b:51, ethertype IPv4 (0x0800), length 98: (tos 0x0, ttl 64, id 1980, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->5ba)!)
            255.255.255.0 > 10.0.100.51: ICMP echo request, id 16367, seq 1, length 64
            09:50:03.673660 00:11:09:d7:2b:fa > 00:22:15:9f:4b:51, ethertype IPv4 (0x0800), length 98: (tos 0x0, ttl 64, id 39043, offset 0, flags [none], proto ICMP (1), length 84, bad cksum 0 (->74f2)!)
            255.255.255.0 > 10.0.100.51: ICMP echo request, id 16367, seq 2, length 64

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

              Well pfsense put it on the wire to the correct mac.. So the problem has nothing to do with pfsense.

              Wrong network masks on the client? What is between pfsense and the client? Switch I assume - any vlans setup on the switch, is the switch dumb?

              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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              • K
                Konstanti @-striker- 0
                last edited by Konstanti

                @striker-0 said in I can ping PFSense but PFSense can't ping back:

                00:11:09:d7:2b:fa
                Hey
                Try so
                System/Advanced/Networking

                0_1548520911335_731de44c-dc6f-4367-9153-db67f4e3d93b-image.png

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                • -
                  -striker- 0
                  last edited by

                  The client is assigned its IP through a static DHCP mapping from pfsense so I don't think it is a wrong network mask. Additionally, pfsense cannot ping any LAN client, i'm just focusing on this one as this is the one I care about pfsense being able to port forward to.

                  There are two dumb switches between pfsense and the client in question. They have both been rebooted several times to clear anything they might be retaining internally.

                  There are no vlans setup in my environment.

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                  • K
                    Konstanti @-striker- 0
                    last edited by

                    @striker-0
                    try check " Disable hardware checksum offloading" in System/Advanced/Networking

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                    • -
                      -striker- 0 @Konstanti
                      last edited by

                      @konstanti I gave that a try, Thank You for the suggest! Rebooted pfsense to ensure it was applied. Same results on a ping test.

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                      • K
                        Konstanti @-striker- 0
                        last edited by Konstanti

                        @striker-0
                        Show the output of the command
                        ifconfig -m
                        and arp -a

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                        • -
                          -striker- 0 @Konstanti
                          last edited by

                          @konstanti The forums are being weird and telling me that the content is flagged as spam. I've attached the requested results as a text file.0_1548526770045_Results.txt

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                          • K
                            Konstanti @-striker- 0
                            last edited by Konstanti

                            @striker-0
                            So in a whole, all looks decently
                            What you can try

                            1. Change the LAN - re0 interface speed (e.g. media 100baseTX mediaopt full-duplex)
                            2. Check the lan re0 - switch cable
                            3. Connect any device directly to PFSense and try to ping .
                            4. check the subnet mask in dhcp server settings and devices that have permanent ip addresses (255.255.255.0)
                            - 1 Reply Last reply Reply Quote 0
                            • chpalmerC
                              chpalmer
                              last edited by chpalmer

                              Client firewalls? If you changed anything such as your LAN subnet your desktops will change to "public" and block everything.

                              Even changing an interface on your router could trigger that.

                              https://www.netgate.com/docs/pfsense/nat/port-forward-troubleshooting.html

                              As you eluded to in your first post- once you figure out why your port forward does not work you will most likely also fix the ping.

                              Triggering snowflakes one by one..
                              Intel(R) Core(TM) i5-4590T CPU @ 2.00GHz on an M400 WG box.

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                              • DerelictD
                                Derelict LAYER 8 Netgate
                                last edited by

                                If you can ping one way and not the other it is almost certainly a firewall on the device you cannot ping blocking it. One way ping success proves two-way traffic, routing (for the most part in most cases), and layer 2 are correct.

                                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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                                • -
                                  -striker- 0 @Konstanti
                                  last edited by

                                  @konstanti

                                  1. I would prefer not to change my link speed. It is currently running at 1000. If I switch it down to 10 or 100, I would be limiting my access to my internet as my internet connection is currently rated for 300. Additionally, this was working previously under the current link state, so I would be surprised if this would resolve anything. What is your rationale for checking this?

                                  2. Tried a different cable, no change in results.

                                  3. Tried connecting a device directly to pfsense. No change in results.

                                  4. Subnet Mask is set to 255.255.255.0 in DHCP and aligns with the client.

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                                  • -
                                    -striker- 0 @chpalmer
                                    last edited by

                                    @chpalmer I thought it could be client side firewall too. I normally leave those disabled on my internal LAN as they just cause unnecessary trouble. I have confirmed and they are still off.

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                                    • DerelictD
                                      Derelict LAYER 8 Netgate
                                      last edited by

                                      Then you'll have to packet capture to see the pings going out and nothing coming back, look at the MAC addresses, etc.

                                      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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                                      • K
                                        Konstanti @-striker- 0
                                        last edited by Konstanti

                                        @striker-0
                                        Reducing the connection speed is just a test
                                        I am very confused by the line in ping test
                                        255.255.255.0 > 10.0.100.51: ICMP echo request, id 16367, seq 0, length 64
                                        ( I don't know what's the subnet mask )

                                        Should be so

                                        length 98: 192.168.1.1 > 192.168.1.230: ICMP echo request, id 30542, seq 0, length 64
                                        length 98: 192.168.1.230 > 192.168.1.1: ICMP echo reply, id 30542, seq 0, length 64
                                        length 98: 192.168.1.1 > 192.168.1.230: ICMP echo request, id 30542, seq 1, length 64
                                        length 98: 192.168.1.230 > 192.168.1.1: ICMP echo reply, id 30542, seq 1, length 64

                                        Can you put the packet capture file here ?

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                                        • -
                                          -striker- 0 @Derelict
                                          last edited by

                                          @derelict I have confirmed the firewall is off. This issue occurs across all devices on my network, the only constant is pfsense. Additionally, within my network other devices can ping each other and I can connect to the port I am trying to forward. Something is going on with pfsense or the hardware it resides on.

                                          K DerelictD 2 Replies Last reply Reply Quote 0
                                          • K
                                            Konstanti @-striker- 0
                                            last edited by

                                            @striker-0
                                            And another question - how much do you have active NORDVPN tunnels ?
                                            if you turn them off, will anything change ?

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