Kernel: arp: runt packet - What could be causing this?



  • My system logs are getting filled with this:

    Jul 20 15:17:00 kernel: arp: runt packet
    Jul 20 15:17:00 kernel: arp: runt packet
    Jul 20 15:17:15 kernel: arp: runt packet
    Jul 20 15:17:15 kernel: arp: runt packet
    Jul 20 15:17:30 kernel: arp: runt packet
    Jul 20 15:17:30 kernel: arp: runt packet
    Jul 20 15:17:45 kernel: arp: runt packet
    Jul 20 15:17:45 kernel: arp: runt packet
    Jul 20 15:18:00 kernel: arp: runt packet
    Jul 20 15:18:00 kernel: arp: runt packet
    Jul 20 15:18:15 kernel: arp: runt packet
    Jul 20 15:18:15 kernel: arp: runt packet
    Jul 20 15:18:30 kernel: arp: runt packet
    Jul 20 15:18:30 kernel: arp: runt packet
    Jul 20 15:18:45 kernel: arp: runt packet
    Jul 20 15:18:45 kernel: arp: runt packet

    This just recently started happening. How can I find what is causing this?


  • Banned

    Well, ARP packet has been received however its size is shorter than suggested by the ARP header. Might be bad switch (port), bad NIC or whatever.



  • Ugh, I think my switch is bad. I replaced it, waited a bit, refreshed and they went away. That sucks I bought it only a year ago. I haven't noticed major network degradation; I might just try to grin and bear it for a while. Thank you.



  • And just like that, still on the faulty switch, the runt packet messages disappear. I will keep an eye on this in the future.



  • I just wanted to followup and give the group a post-mortem on this issue. The culprit behind these seems to have been a backup cell phone we keep around the house in case one gets broken, which I turned off around the time of my previous post. I have roughly 3 or 4 devices on wireless in my house and to be honest, I thought this would've been due to one of the 18 wired drops I have throughout the house (poor wiring, bad NIC, etc.)

    I have actually pulled the battery from the phone for the time being but I'm thinking about finding some kind of packet sniffer for Android to see if I can clearly see the packets in question. Interesting exercise.

    In the past couple days of searching though, I never found any way to identify the source interface of these runt packets within Pfsense; am I missing something? If not, would it be logical/practical to add something like that to the System Logs?

    EDIT: Could a mod move this out of the 2.1 Snapshot forum, since this doesn't directly relate to functions within 2.1?