unable to delete "unreachable" entries from arp cache

Question

Hi all,
I'm struggling with this Windows 10 issue.

My main problem is that I have to clear local dns as I can't resolve correctly one name of a PC.

if I ping myPC I get a wrong IP

I found that the arp cache still keep this wrong (old) IP, using this command:

netsh interface ipv4 show neighbors

then I tried:

arp -d

netsh interface ipv4 delete neighbors "interface name"

both command get me a successfull feedback but I still see the old/wrong IP in the table

more, after the above cmds, I see that only the "unreachable" entries remains in the table, cleared the other...

how can I force the removing everything?, also the "unreachable" entries?

thanks

Answer 1

Hi,

Thanks for posting in Q&A platform.

Please try to run this command in PowerShell with administrator privilege to see if the specific ARP entry can be deleted.

netsh interface ipv4 delete neighbor "interface name" 10.1.1.1 aa-bb-cc-dd-ee-ff store=persistent

Based on provided information, my understanding is the hostname of a PC cannot be resolved correctly. If the issue still existed, please run the following command in a CMD window to see if the hostname can be resolved to a correct IP by DNS server:

ipconfig /flushdns

nslookup /hostname of PC

Best Regards,
Sunny

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Answer 2

Hi Sunny, thanks for your suggestions.

I find the wrong IP address in both WiFi and Ethernet interfaces, like below:

Interface 16: WiFi
Internet Address                              Physical Address   Type
--------------------------------------------  -----------------  -----------
...
192.168.178.122                               Unreachable        Unreachable
...

Interface 18: Ethernet
Internet Address                              Physical Address   Type
--------------------------------------------  -----------------  -----------
...
192.168.178.122                               00-00-00-00-00-00  Unreachable
...

When I run (without subinterfaces, as I haven't):

netsh interface ipv4 delete neighbor "WiFi" 192.168.178.122 store=persistent

I get:

Element not found.

for both interfaces

If I run:

nslookup myPCname

I get:

Server:  fritz.box
Address:  192.168.178.1

Name:    myPCname.fritz.box
Addresses:  192.168.178.122
          192.168.178.50

then it resolves, as first, the wrong IP address (the second one is the right one)

I don't know what else to do any longer...