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    Change default TTL value

    Scheduled Pinned Locked Moved General pfSense Questions
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    • B
      bkcberry
      last edited by

      Hey guys, quick question. I can run the command```
      sysctl net.inet.ip.ttl=128

      
      

      net.inet.ip.ttl=128

      
      to /etc/sysctl.conf and reboot, nothing happens. Anyone know how to make this stick?
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      • johnpozJ
        johnpoz LAYER 8 Global Moderator
        last edited by

        you would create it in the gui section for that.

        tunables.png_thumb
        tunables.png

        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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        • B
          bkcberry
          last edited by

          Awesome, thanks!!

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          • johnpozJ
            johnpoz LAYER 8 Global Moderator
            last edited by

            If you don't mind why are you needing to change the ttl - that damn curiosity kat of mine is a PITA ;)

            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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            • JKnottJ
              JKnott
              last edited by

              If you don't mind why are you needing to change the ttl - that damn curiosity kat of mine is a PITA ;)

              I was wondering the same thing.

              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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              • johnpozJ
                johnpoz LAYER 8 Global Moderator
                last edited by

                I saw an issue long time ago 2012 where the dhcp client was setting low ttl of 16 and someone in the EU was unable to get dhcp from their isp.. because it was so many hops away.  Had to recompile the dhcp client for them - even filed a bug with freebsd, which they finally fixed in 2014, like 1 month shy of 2 years later ;)

                But other than something like that not sure why would need to change the ttl..

                Here is the bug I filed - its the only freebsd bug I ever filed ;)
                https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=170279

                But something like that is really only reason why I would think you would have to set that.. So yeah that damn kat keeps meowing at me on what the problem is ;)

                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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                • JKnottJ
                  JKnott
                  last edited by

                  ^^^^
                  A quick peek with Wireshark shows TTL/Hop Limit of 64 outgoing and various values in the 50s incoming.

                  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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                  • johnpozJ
                    johnpoz LAYER 8 Global Moderator
                    last edited by

                    Yeah 64 is common default.. 128 is a lot of freaking hops ;)  Which is why so curious to why would need to change to 128..

                    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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                    • JKnottJ
                      JKnott
                      last edited by

                      @johnpoz:

                      Yeah 64 is common default.. 128 is a lot of freaking hops ;)  Which is why so curious to why would need to change to 128..

                      Maybe he has a really BIG network.  ;)

                      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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