Network Troubleshooting / IT Support Guides
Inspect the local neighbor cache during LAN failures
A host on the same subnet may be unreachable because its address resolves to an unexpected local hardware address. Inspect the neighbor cache alongside switch evidence.
Environment and inputs: Mixed platforms · each example identifies its shell or required tool
Try the diagnostic command
Use the stated shell and platform. Replace sample domains, addresses, services and paths with values from the system you are authorized to support.
Get-NetNeighbor -AddressFamily IPv4How to read the result
Windows PowerShell displays neighbor addresses, link-layer addresses and reachability state. Stale entries are normal cache states and do not by themselves prove a broken connection.
What to do next
Compare the affected IP's mapping with approved asset and switch information. If duplicate addressing is suspected, preserve the timestamps and involve the network team to locate both devices.
Before you make a change
The cache covers local-link neighbors or next hops, not the MAC address of every internet destination. Do not clear all entries before recording evidence.