Windows homelab LAN:

How come arp -d does not work consistently? I run the command and the ARP table is not cleared, yet when I run it again a few moments later it does work but leaves certain machines and not others in its table.

Also, in the ARP table, in the "type" field it will label a certain machine as "dynamic" when it is a static IP--or is dynamic and static used differently here? Thanks.

  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Aug 7, 2017 at 22:02

2 Answers 2


You cannot delete the arp cache for a node for which there is an active conversation -- it'll just relearn it instantly.

"Dynamic" and "static" have to do with the ARP TABLE itself. A static entry is one you manually added. Dynamic is one learned on the wire.

  • But like OP asked, it looks like the static dynamic type is switched in Windows. It shows my local IP as dynamically learnt and then there are some IPs like, etc that are statically learnt. Shouldn't your local IP be statically learnt and the rest dynamically?
    – Izy-
    Jul 7, 2016 at 5:02
  • 2
    Multicast addresses are static. Your own IP/MAC shouldn't be in the table -- you don't talk to yourself on the wire, but may appear due to duplicate address detection.
    – Ricky
    Jul 7, 2016 at 5:33

Remember, it's MAC addresses and ARP for comm between workstation and switches and it's IP addresses and routers for comm to remote networks.

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