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    Repeated warnings in OpenVPN log

    Scheduled Pinned Locked Moved OpenVPN
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    • P
      pfsensory
      last edited by

      I have repeated warnings in my OpenVPN logs:

      xxx.xxx.xxx.xxx:61586 WARNING: Bad encapsulated packet length from peer (18245), which must be > 0 and <= 1575 – please ensure that --tun-mtu or --link-mtu is equal on both peers -- this condition could also indicate a possible active attack on the TCP link -- [Attempting restart…]

      These seem to be present even when no client is connected to my pfSense OpenVPN server (although the pfSense box is still connected as an OpenVPN client to another OpenVPN server).

      What is causing these entries?  And is there a setting I can alter to prevent the problem (if in fact there is a problem)?

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      • P
        pfsensory
        last edited by

        (bump)

        Anyone?

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        • jimpJ
          jimp Rebel Alliance Developer Netgate
          last edited by

          It could be junk packets hitting the port. Non-OpenVPN traffic attempting to talk to it, like a port scanner.

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          • P
            pfsensory
            last edited by

            That makes sense.  I notice, however, that some of the warnings have a source IP that is internal to my network.  How would one explain that?

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