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    Am I being DoS attacked?

    Scheduled Pinned Locked Moved General pfSense Questions
    24 Posts 5 Posters 2.1k Views
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    • F
      furom @stephenw10
      last edited by furom

      @stephenw10 said in Am I being DoS attacked?:

      That is pass inbound on the WAN so you have some firewall rules on the WAN allowing it. What are they?

      Most definitely not?! That is way beyond anything intentional if that is really the case... I have no rules in WAN other than default, then a floating for blocking outbound RFC1918 to WAN

      This is all my WAN rules;
      69998125-e4df-4932-b6f3-27ccff023f6f-image.png
      And the floating RFC1918 block;
      e05d98f4-8639-4608-a63f-68850714538d-image.png

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      • stephenw10S
        stephenw10 Netgate Administrator
        last edited by

        Then likely replies to outbound connections from something. Not a DoS attack in that case.

        I would expect to see some outbound traffic at the time but perhaps you just disabled that on the graph?

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        • F
          furom @stephenw10
          last edited by

          @stephenw10 said in Am I being DoS attacked?:

          Then likely replies to outbound connections from something. Not a DoS attack in that case.

          I would expect to see some outbound traffic at the time but perhaps you just disabled that on the graph?

          Unfortunately I did disable that. Now when I go back I see nothing at the same timestamp... :(

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          • stephenw10S
            stephenw10 Netgate Administrator
            last edited by

            Not even a tiny increase? It only required minimal outbound traffic to request a much larger replies.

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            • F
              furom @stephenw10
              last edited by furom

              @stephenw10 said in Am I being DoS attacked?:

              Not even a tiny increase? It only required minimal outbound traffic to request a much larger replies.

              Think I managed to create a view that shows it, not so great with these graphs. It is based on the same data as the first, but custom and just showing the hour it happened;
              6329109c-434d-44bb-85e6-9ea0a63bf451-image.png
              Looks to me as if "delay average" dipped at the time, whatever that is?

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              • stephenw10S
                stephenw10 Netgate Administrator
                last edited by

                That's the ping time to the gateway so it's not like it caused increased WAN latency.

                The outpass total value is what I'd be looking at there and it's too small to see in that graph.

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                • F
                  furom @stephenw10
                  last edited by

                  @stephenw10 said in Am I being DoS attacked?:

                  That's the ping time to the gateway so it's not like it caused increased WAN latency.

                  The outpass total value is what I'd be looking at there and it's too small to see in that graph.

                  Agreed. Just so strange, and a little unsettling... Can I add some sort of logging that can be left running if it should happen again?

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                  • F
                    furom @furom
                    last edited by

                    @furom This may help some?
                    f31c3d4e-5ee0-45f0-b1a0-dba16be9ae65-image.png

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                    • stephenw10S
                      stephenw10 Netgate Administrator
                      last edited by

                      Not really. That's pretty much what I'd expect to see for that level of downloading.

                      Basically it looks like something in your network downloaded something. Not especially unusual.

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                      • F
                        furom @stephenw10
                        last edited by

                        @stephenw10 That's at least something good then. The stuttering is a bit annoying, but happens rarely so if there is nothing else that ought to be done, I'll let it be then. Thanks

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                        • stephenw10S
                          stephenw10 Netgate Administrator
                          last edited by

                          You'd only really expect it to cause issues with other traffic if it was filling the available WAN bandwidth. You might just not be seeing the actual peak there because of the averaging in the RRD graphs.

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                          • F
                            furom @stephenw10
                            last edited by

                            @stephenw10 That may be so of course. Where would I find the data graphs are generated from? Perhaps it will give some more details?

                            NightlySharkN stephenw10S 2 Replies Last reply Reply Quote 0
                            • NightlySharkN
                              NightlyShark @furom
                              last edited by NightlyShark

                              @furom Just to add my 2 cents here, proprietary streaming services (and we all know who we are talking about, for music at least) can sometimes create TCP tunnels that pass a UDP stream on the inside. And, in some cases, this could lead to dropped states (the firewall closes the connection because it considers it to be stale) because the keep-alive of the service is too low, coupled with a fast connection that has loaded the whole song or podcast longer than the keep-alive of the connection.

                              Maybe try changing the state policy of PfSense to conservative (System->Advanced->Firewall and NAT->Packet Processing->Firewall Optimization Options)?

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                              • F
                                furom @NightlyShark
                                last edited by

                                @nightlyshark Thanks, that can be an option. But as is now it happens rarely so was more interested in finding the cause if possible. I will remember this if it gets worse though :)

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                                • stephenw10S
                                  stephenw10 Netgate Administrator @furom
                                  last edited by

                                  @furom said in Am I being DoS attacked?:

                                  Where would I find the data graphs are generated from? Perhaps it will give some more details?

                                  You can find the rrd files the graphs are generated from in /var/db/rrd but there will not be any more data there than the graphs can display. The purpose of RRD is to retain older data at lesser resolution.

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                                  • F
                                    furom @stephenw10
                                    last edited by

                                    @stephenw10 Oh, thanks. Was for a bit hoping the opposite... :)

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                                    • provelsP
                                      provels
                                      last edited by

                                      TL;DR, but maybe it's a bot port scanning for commonly used ports?

                                      Peder

                                      MAIN - pfSense+ 24.11-RELEASE - Adlink MXE-5401, i7, 16 GB RAM, 64 GB SSD. 500 GB HDD for SyslogNG
                                      BACKUP - pfSense+ 23.01-RELEASE - Hyper-V Virtual Machine, Gen 1, 2 v-CPUs, 3 GB RAM, 8GB VHDX (Dynamic)

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                                      • F
                                        furom @provels
                                        last edited by

                                        @provels said in Am I being DoS attacked?:

                                        TL;DR, but maybe it's a bot port scanning for commonly used ports?

                                        Well, It could be, but that intense it affects other traffic?

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                                        • stephenw10S
                                          stephenw10 Netgate Administrator
                                          last edited by

                                          What is your WAN download bandwidth? If it's significantly larger than 2.7Mbps, which I imagine it is, then a short download like that really should affect other traffic. The other thing it might be is a large number of new connections or maybe a very large number of small packets.

                                          It's almost certainly not some external scan/attack because that is pass traffic on WAN. So replies to something internal connecting out in this case.

                                          Steve

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                                          • F
                                            furom @stephenw10
                                            last edited by

                                            @stephenw10 I think I have 250 down, so yes, should be plenty of bandwidth left. And the passin-traffic, I checked this while watching Youtube, and well, it comes really close. So don't think the 2.7Mb is what made things stutter... Almost as if someone pressed pause/play really fast (which I hope is not the case)
                                            Once I sat on my remote, but don't think that was it this time... :D

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