I just discovered an anomaly on my network that has presumably been going for some time. My wife's laptop ( alias Sarahs-ROG.local) is sending ARPs for huge blocks of IPs to broadcast asking for through (My DHCP pool starts at and goes to 149. Coincidence?)

This traffic is recorded from my PC ( on another switchport. Discovery Lunacy

I attempted to resolve it by disabling a number of her Windows 10 networking things (Discovery, Homegroup, File sharing, and possibly more), but nothing stopped the flood of ARPs and LLMNRs.

What is causing this?

EDIT: The plot thickens! It stops the ARP broadcasts to that ipv4 range mentioned above when I turn my Canon printer on. It continues the merciless LLMNR assaults, though.

  • Arp requests are expected if you have devices on those addresses. Are they? The LLMNR requets look like you have "automatically detect proxy" in the browser.
    – Paul
    Nov 25, 2015 at 23:30
  • @Paul Only a few devices, and only about 10 at any given time. This block repeats constantly, not just once. Also, added a note about the printer.
    – Tim G
    Nov 25, 2015 at 23:39
  • Ok, so it looks like the Canon print driver on the laptop is looking for a printer, and it stops when it finds one.
    – Paul
    Nov 25, 2015 at 23:41
  • @Paul Ok, seeing you say the auto-proxy thing helps, I see now that's what it's doing. I turned it off in Windows' settings and it continued, but killing Chrome seems to have done it. Any idea about how to curb this printer driver's abusive networking?
    – Tim G
    Nov 25, 2015 at 23:44
  • IJ Network Scanner Selector EX was the application to solve it. I opened the Scan from Operations panel and unchecked the printer. Much better, now. @Paul, you've got my thanks on the answer here; go ahead and note it so I can accept it, unless there's a way to select a comment as a best answer.
    – Tim G
    Nov 26, 2015 at 0:03

1 Answer 1


The "wpad" at the end of the LLMNR requests suggest that these are coming from proxy auto-detection in Internet Settings, or in the browser settings. It looks for a device with the name "wpad" and attempts to download a proxy configuration script from it.

The ARP requests appear to becoming from the Printer / Scanner software - while the printer is off, the software scans the local network trying to find the scanner, then stops looking once the printer is turned on.

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