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    Strange behaviour for ICMP (ping) rule on WAN interface

    General pfSense Questions
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    • stephenw10S
      stephenw10 Netgate Administrator
      last edited by

      Ah, is it not just a vswitch in VMWare between pfSense and the .5 VM then?

      Even so you can probably just do the tagging in VMWare so pfSense just sees two separate NICs.

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        mauro.tridici @stephenw10
        last edited by

        @stephenw10 Good morning, Stephen.

        This is to inform you that I just checked the number of free interfaces on the VMware hypervisor. Unfortunately, there is no free interface to be dedicated to the "public LAN".

        Anyway, before giving up, I made a search on pfSense Forum looking for "pfsense vlan bridge" and I found this interesting topic:

        https://forum.netgate.com/topic/136900/help-with-vlans-in-bridge/23?_=1667375382000

        In particular, at the end of discussion, I read that "broonu" user says:

        With tcpdump i see the ARP Request but pfsense dont send the ARP Reply.
        Im going to clear everything and reconfigure from scratch.

        and it seems he solved his issue with the following action:

        @delerict thank you for your time and help!
        it was a vmware misconfiguration, e1000 nic instead of vmxnet3.

        After reading that, I checked the type of virtual nic assigned to WAN and "public LAN" interfaces of my pfSense instance and I noticed that the interfaces type is E1000. So, I decided to reply to "broonu" user with the following message:

        @broonu Hello, sorry if I'm replying to this old topic, but I'm experiencing the same problem trying to bridge the WAN interface with a VLAN created on a LAN interface.

        The behavior is almost the same: no reply to ARP requests from pfsense + I cant ping the pfsense upstream gateway.

        Before giving up, I noticed that the WAN and LAN interfaces are E1000 (not VMXNET3).
        I would like to change the nic type as last attempt.
        Anyway, before doing that, I would like to know if there is a particolar relation between bridge and vmxnet3.

        Could you please help me?
        Thanks

        In addition, I would like to answer your question:

        Ah, is it not just a vswitch in VMWare between pfSense and the .5 VM then?

        Yes, it is not just a vswitch in VMware between pfSense and the .5 VM. Virtual router and pfsense are on the same hypervisor, but the "client" machines (virtual and physical ones) are connected to pfSense through a switch.

        Even so you can probably just do the tagging in VMWare so pfSense just sees two separate NICs.

        This is the current configuration:

        • physical pfSense interface em0 (WAN) is connected to the router;
        • physical pfSense interface em6 is connected to a vswitch (named "LAN") that has been configured to manage/accept all VLANs (trunk mode);
        • on vmware side, the vswitch mentioned above is logically connected to a TRUNK port on the physical switch;
        • on pfsense side, several VLANs have been created adding tags (for example, "VLAN em6.90", "VLAN em6.10" and so on);
        • the VM is connected to an ACCESS port (with VLAN ID 90) on the same physical switch.

        If you think that the main cause is still the VLAN over the bridge (and not the E1000 nic type), could you help me to better understand how to apply your last suggestion?

        Thanks in advance,
        Mauro

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        • M
          mauro.tridici @mauro.tridici
          last edited by

          @stephenw10

          I think I understand your suggestion:

          On vmware side, on top fo the vswitch "LAN" (the one that accepts every VLAN), I created a portgroup named "Public LAN" with tag 90.
          I also added a virtual nic to the pfsense instance (let's say, em8) and I connected this nic to the "Public LAN" portgroup.

          So, in this new situation, em8 will be a new interface of pfsense without any VLAN on top of itself.

          As soon as possible, I will do a reboot of pfsense and I will test the bridge again.
          If it will fail, I will try also to change E1000 to VMXNET3.

          Crossing fingers,
          Mauro

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          • stephenw10S
            stephenw10 Netgate Administrator
            last edited by

            Yes, that's what I meant. So pfSense sees only the virtual NIC without a VLAN but VMWare tags the traffic before it leaves.

            If changing the virtual NIC type makes any difference there I would expect it to be because the hardware off-loading options between them are different.

            Steve

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            • M
              mauro.tridici @stephenw10
              last edited by

              Dear @stephenw10 ,

              nothing to do, my first attempt (using em8 interface without any VLAN) failed.
              The behaviour is always the same. Doing pcap on pfsense involved interfaces, I can see the .5 requests, but without any reply.
              If remove the bridge and I assign 10.10.10.1 IP to the "Public LAN" interface, I can ping it successfully from the VM (10.10.10.2).

              So, I decided to go ahead trying with the nic type change from E1000 to VMXNET3.
              After powering off the VM, I made the needed changes to the WAN and "Public LAN" interfaces (at least). But this action changed the MAC address of the interfaces and, after rebooting the VM, pfSense ask me to reassign the interfaces and recreate the VLANs.
              This is due to the new Interfaces names vmx1, vmx2, vmx3 instead of em1, em2 and so on...
              Unfortunately I can't assign the VLAN em6.X to the vmx2 interface since the VLAN for vmx2 has not been yet created.

              Now, pfsense has been restored from a backup.
              Is there a particular procedure to change the nic type without reconfigure the entire pfsense?

              Thanks in advance,
              Mauro

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              • stephenw10S
                stephenw10 Netgate Administrator
                last edited by

                You can rename the interfaces in the config file manually and then restore it.

                It's possible to create the new VLANs at the CLI (so vmx6.90) and then assign them to the interfaces but it can get a bit complex if you have lot.

                If you only have that one VLAN you could reassign it to some other interface temporarily (if you have any spare) and then create the new VLAN on vmx after swapping it in and assign it back.

                Steve

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                • M
                  mauro.tridici @stephenw10
                  last edited by

                  @stephenw10

                  Hello Stephen,

                  something changed after moving from E1000 to VMXNET3 nics type.
                  The problem seems to be still here, but I think that your professional experience could help to resolve the issue.

                  In order to do some test without involving the pfSense instance that is in production, I preferred to perform the following steps:

                  • clone of the production pfSense instance;
                  • change of the nic type from E1000 to VMXNET3 (only for the WAN and "Public LAN" interfaces);
                  • update of the pfsense interfaces names (vmx0 for the WAM, vmx2 for the public LAN);
                  • assignment of a new public IP (belonging to the same public subnet mentioned in the messages above) to the WAN interface (y.y.y.15/25);
                  • disconnection of every virtual interface defined on the pfsense instance (except for WAN and public LAN).

                  After that, I started doing some test.

                  Ping from VM (IP .5) to pfSense (IP .15):

                  output on VM:
                  ping y.y.y.15 (ping seems waiting for the answer)

                  output on PFSENSE:
                  [2.5.2-RELEASE][admin@pfSense_LAN_CMCC.home.arpa]/root: tcpdump -i vmx2 host y.y.y.5
                  tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
                  listening on vmx2, link-type EN10MB (Ethernet), capture size 262144 bytes
                  15:08:35.989761 ARP, Request who-has y.y.y.5 tell y.y.y.1, length 46
                  15:08:36.780956 IP y.y.y.5 > y.y.y.15: ICMP echo request, id 19822, seq 65, length 64
                  15:08:36.780982 ARP, Request who-has y.y.y.5 tell y.y.y.15, length 28
                  15:08:37.004806 ARP, Request who-has y.y.y.5 tell y.y.y.1, length 46
                  15:08:37.780931 IP y.y.y.5 > y.y.y.15: ICMP echo request, id 19822, seq 66, length 64
                  15:08:37.780952 ARP, Request who-has y.y.y.5 tell y.y.y.15, length 28
                  15:08:38.028828 ARP, Request who-has y.y.y.5 tell y.y.y.1, length 46
                  15:08:38.780927 IP y.y.y.5 > y.y.y.15: ICMP echo request, id 19822, seq 67, length 64
                  15:08:38.780965 ARP, Request who-has y.y.y.5 tell y.y.y.15, length 28
                  15:08:39.780917 IP y.y.y.5 > y.y.y.15: ICMP echo request, id 19822, seq 68, length 64
                  15:08:39.780966 ARP, Request who-has y.y.y.5 tell y.y.y.15, length 28
                  15:08:40.780948 IP y.y.y.5 > y.y.y.15: ICMP echo request, id 19822, seq 69, length 64
                  15:08:40.781007 ARP, Request who-has y.y.y.5 tell y.y.y.15, length 28

                  Now, the ICMP request can reach PFSENSE, but PFSENSE didn't reply to this request.
                  It seems that something is blocking this kind of traffic.

                  Ping from VM (IP .15) to pfSense (IP .5):

                  [2.5.2-RELEASE][admin@pfSense_LAN_CMCC.home.arpa]/root: ping y.y.y.5
                  PING y.y.y.5 (y.y.y.5): 56 data bytes
                  ping: sendto: Host is down
                  ping: sendto: Host is down

                  ARP TABLE on PFSENSE:

                  [2.5.2-RELEASE][admin@pfSense_LAN_CMCC.home.arpa]/root: arp -a
                  ? (192.168.120.1) at 00:0c:29:db:d8:06 on vmx3.192 permanent [vlan]
                  ? (10.0.0.1) at 00:0c:29:db:d8:06 on vmx3.10 permanent [vlan]
                  ? (192.168.44.1) at 00:0c:29:db:d8:d4 on lagg0.44 permanent [vlan]
                  ? (192.168.43.1) at 00:0c:29:db:d8:d4 on lagg0.43 permanent [vlan]
                  ? (192.168.40.1) at 00:0c:29:db:d8:d4 on lagg0.40 permanent [vlan]
                  ? (192.168.34.1) at 00:0c:29:db:d8:d4 on lagg0.34 permanent [vlan]
                  ? (192.168.33.1) at 00:0c:29:db:d8:d4 on lagg0.33 permanent [vlan]
                  ? (192.168.32.1) at 00:0c:29:db:d8:d4 on lagg0.32 permanent [vlan]
                  ? (192.168.31.1) at 00:0c:29:db:d8:d4 on lagg0.46 permanent [vlan]
                  ? (192.168.30.1) at 00:0c:29:db:d8:d4 on lagg0.30 permanent [vlan]
                  ? (y.y.y.5) at 00:0c:29:2b:ee:a6 on vmx2 expires in 1109 seconds [ethernet]
                  ? (y.y.y.15) at 00:0c:29:db:d8:c0 on vmx0 permanent [ethernet]
                  ? (y.y.y.1) at 00:0c:29:02:f1:99 on vmx0 expires in 1200 seconds [ethernet]
                  ? (192.168.100.1) at 00:0c:29:db:d8:f2 on em4 permanent [ethernet]
                  pfSense_LAN_CMCC.home.arpa (192.168.240.2) at 00:0c:29:db:d8:de on em2 permanent [ethernet]

                  ARP TABLE on VM:

                  gateway (y.y.y.1) at <incomplete> on ens192
                  ? (y.y.y.15) at 00:0c:29:db:d8:10 [ether] on ens912

                  It seems that the bridge is allowing the traffic from VM to pfsense and is blocking the traffic from pfsense to VM.
                  Do you have some other idea about the cause of this issue?

                  Many thanks in advance,
                  Mauro

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                  • M
                    mauro.tridici @mauro.tridici
                    last edited by

                    It seems that pfsense is trying to reach the .5 using a different route.
                    Maybe it is trying to do it via the upstream gateway .1. But VM .5 is not "on internet", it is behind the firewall itself.

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                    • stephenw10S
                      stephenw10 Netgate Administrator
                      last edited by

                      pfSense there is sending an ARP request for .5 every second. So probably each time it tries to reply to a ping. That implies it never sees a response. And in fact the pcap never shows the VM responding to those requests.
                      The odd thing there is that the pfSense ARP table appears to have an entry for .5 even though it's still sending queries for it. Was that taken after the pings stopped?

                      Steve

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                      • M
                        mauro.tridici @stephenw10
                        last edited by

                        @stephenw10
                        No it was taken during the ping.
                        This is what I see when the ping is stopped:

                        [2.5.2-RELEASE][admin@pfSense_LAN_CMCC.home.arpa]/root: tcpdump -i vmx2 host y.y.y.5
                        tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
                        listening on vmx2, link-type EN10MB (Ethernet), capture size 262144 bytes
                        15:31:05.356375 ARP, Request who-has y.y.y.5 tell y.y.y.1, length 46
                        15:31:06.382707 ARP, Request who-has y.y.y.5 tell y.y.y.1, length 46
                        15:31:07.406663 ARP, Request who-has y.y.y.5 tell y.y.y.1, length 46
                        15:31:13.187718 ARP, Request who-has y.y.y.5 tell y.y.y.1, length 46
                        15:31:14.190695 ARP, Request who-has y.y.y.5 tell y.y.y.1, length 46
                        15:31:15.214728 ARP, Request who-has y.y.y.5 tell y.y.y.1, length 46
                        15:31:22.649162 ARP, Request who-has y.y.y.5 tell y.y.y.1, length 46
                        15:31:23.662695 ARP, Request who-has y.y.y.5 tell y.y.y.1, length 46
                        15:31:24.686714 ARP, Request who-has y.y.y.5 tell y.y.y.1, length 46

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                        • stephenw10S
                          stephenw10 Netgate Administrator
                          last edited by

                          Right but you still see an entry in the ARP table in pfSense for .5?

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                          • M
                            mauro.tridici @stephenw10
                            last edited by

                            @stephenw10 I just checked, I don't see any entry for .5 :-(
                            Do you think that I should give up?

                            Is my opinion wrong?

                            It seems that pfsense is trying to reach the .5 using a different route.
                            Maybe it is trying to do it via the upstream gateway .1. But VM .5 is not "on internet", it is behind the firewall itself.

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                            • stephenw10S
                              stephenw10 Netgate Administrator
                              last edited by

                              This looks like a layer 2 issue. pfSense is sending ARP requests and the VM never replies, so it's probably not seeing them. A pcap on the VM would confirm that.

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                              • M
                                mauro.tridici @stephenw10
                                last edited by

                                I still don't understand why everything works if I assign a static IP to the "public LAN" interface... connectivity stops working as soon as the bridge is enabled.
                                Why VM stops sending ARP replies as soon as I change the IP address?

                                I don't want to disturb you again, sorry.
                                I'm doing these questions to myself :)

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                                • stephenw10S
                                  stephenw10 Netgate Administrator
                                  last edited by stephenw10

                                  Is the VM actually seeing the ARP requests? More likely the virtual interface is not sending them from pfSense because to do so it has to use the wrong MAC address. That's why it needs to be in promiscuous mode. Likely something has to be set in VMWare to allow that for the hypervisor side.

                                  https://kb.vmware.com/s/article/1004099

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                                  • M
                                    mauro.tridici @stephenw10
                                    last edited by

                                    Thank you, Stephen.
                                    The Wan and "Public LAN" interfaces (and related switches) are in promiscuous mode. Also the VM interface and vswitch is in promiscuous mode.

                                    If I run "tcpdump -I ens192" on the VM, I can see only the STP lines:

                                    3: ens192: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
                                    link/ether 00:0c:29:2b:ee:a6 brd ff:ff:ff:ff:ff:ff
                                    inet y.y.y.5/25 brd 90.147.177.127 scope global noprefixroute ens192
                                    valid_lft forever preferred_lft forever
                                    inet6 fe80::20c:29ff:fe2b:eea6/64 scope link
                                    valid_lft forever preferred_lft forever

                                    [root@test-hs01 ~]# tcpdump -i ens192
                                    tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
                                    listening on ens192, link-type EN10MB (Ethernet), capture size 262144 bytes
                                    15:37:24.676212 STP 802.1w, Rapid STP, Flags [Learn, Forward, Agreement], bridge-id 8000.f8:8e:a1:73:f9:81.8016, length 43
                                    15:37:26.678015 STP 802.1w, Rapid STP, Flags [Learn, Forward, Agreement], bridge-id 8000.f8:8e:a1:73:f9:81.8016, length 43
                                    15:37:28.679573 STP 802.1w, Rapid STP, Flags [Learn, Forward, Agreement], bridge-id 8000.f8:8e:a1:73:f9:81.8016, length 43
                                    15:37:30.681543 STP 802.1w, Rapid STP, Flags [Learn, Forward, Agreement], bridge-id 8000.f8:8e:a1:73:f9:81.8016, length 43
                                    15:37:32.683314 STP 802.1w, Rapid STP, Flags [Learn, Forward, Agreement], bridge-id 8000.f8:8e:a1:73:f9:81.8016, length 43
                                    15:37:34.684944 STP 802.1w, Rapid STP, Flags [Learn, Forward, Agreement], bridge-id 8000.f8:8e:a1:73:f9:81.8016, length 43

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                                    • stephenw10S
                                      stephenw10 Netgate Administrator
                                      last edited by

                                      pfSense will only ARP for it when it's trying to send traffic to it. So when either pfSense is trying to ping the VM or when the VM is pinging pfSense and it's trying to reply.

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                                      • M
                                        mauro.tridici @stephenw10
                                        last edited by

                                        @stephenw10 yes, you are right, thank you.

                                        If I make a ping from VM to PFSENSE, on pfSense I can see the correct ARP line:

                                        [2.5.2-RELEASE][admin@pfSense_LAN_CMCC.home.arpa]/root: arp -a|grep y.y.y.5
                                        ? (y.y.y.5) at 00:0c:29:2b:ee:a6 on em8 expires in 1180 seconds [ethernet]
                                        ? (y.y.y.5) at (incomplete) on em0 expired [ethernet]

                                        But, I also noticed that there is an incomplete ARP line related to .5 IP.
                                        And this line contains some reference to the em0 interfaces (that is the WAN interface for pfSense).

                                        Is it normal or should I investigate on it?

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                                        • stephenw10S
                                          stephenw10 Netgate Administrator
                                          last edited by

                                          Well they are in the same layer 2 so the normal things don't really apply there. Do you see the ARPs or ping replies in a pcap on either device?

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                                            mauro.tridici @stephenw10
                                            last edited by

                                            @stephenw10

                                            Do you see the ARPs or ping replies in a pcap on either device?

                                            I'm not sure I have correctly got it.
                                            Do you mean that I should run a pcap on both the interfaces (em0 and em8) while a ping from the VM is running?

                                            Thank you

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