Ntop showing 54% bad packets on internet interface

  • I'm assuming this is some sort of anomaly.  Anyone else using ntop and seeing an inordinate number of packets with bad checksums on their internal interface?  Isn't that usually a sign of a bad cable or bad network card/port?  Or is this some strange dynamic between freebsd and ntop?

    Scratching my head….


  • Could be caused by checksum offload, I believe.

    Edit: IOW checksum offload would make the checksum calculation invisible to ntop, it'd see all outgoing traffic as having a bad checksum. Not that you should disable checksum offload and that will fix the problem (though it probably will appear to).

  • Rebel Alliance Developer Netgate

    Others have reported the same thing, where ntop reports just over 50% of traffic as bad.

    I believe it did have something to do with checksum offloading or NAT causing some checksums to appear bad.

    Either way it seems to be purely cosmetic.