Public/network/Clear-Arp.ps1
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#Requires -Version 5.1 function Clear-Arp { <# .SYNOPSIS Clears the ARP (Address Resolution Protocol) cache on the local machine .DESCRIPTION Removes all entries from the ARP cache by executing 'netsh interface ip delete arpcache'. This forces the system to re-resolve MAC addresses for all IP destinations, which can help resolve network connectivity issues caused by stale or incorrect ARP entries. Requires administrator privileges to execute. .EXAMPLE Clear-Arp Clears the entire ARP cache on the local machine. .EXAMPLE Clear-Arp -WhatIf Shows what would happen without actually clearing the ARP cache. .EXAMPLE Clear-Arp -Verbose Clears the ARP cache with verbose output showing execution details. .OUTPUTS None This function does not produce pipeline output. .NOTES Author: Franck SALLET Version: 1.0.0 Last Modified: 2026-03-20 Requires: PowerShell 5.1+ / Windows only Requires: Administrator privileges (netsh interface ip delete arpcache) .LINK https://github.com/k9fr4n/PSWinOps .LINK https://learn.microsoft.com/en-us/windows-server/networking/technologies/netsh/netsh-interface-ip #> [CmdletBinding(SupportsShouldProcess, ConfirmImpact = 'Medium')] [OutputType([void])] param() begin { Write-Verbose "[$($MyInvocation.MyCommand)] Starting ARP cache clear operation" if (-not (Test-IsAdministrator)) { $PSCmdlet.ThrowTerminatingError( [System.Management.Automation.ErrorRecord]::new( [System.UnauthorizedAccessException]::new('Clear-Arp requires Administrator privileges.'), 'ElevationRequired', [System.Management.Automation.ErrorCategory]::PermissionDenied, $null ) ) } $netshPath = Join-Path -Path $env:SystemRoot -ChildPath 'System32\netsh.exe' if (-not (Test-Path -Path $netshPath -PathType Leaf)) { $PSCmdlet.ThrowTerminatingError( [System.Management.Automation.ErrorRecord]::new( [System.IO.FileNotFoundException]::new("netsh.exe not found at '$netshPath'."), 'NetshNotFound', [System.Management.Automation.ErrorCategory]::ObjectNotFound, $netshPath ) ) } } process { if ($PSCmdlet.ShouldProcess('Local ARP cache', 'Delete all entries')) { try { Write-Verbose "[$($MyInvocation.MyCommand)] Running: netsh interface ip delete arpcache" $result = Invoke-NativeCommand -FilePath $netshPath -ArgumentList @('interface', 'ip', 'delete', 'arpcache') if ($result.ExitCode -ne 0) { Write-Error "[$($MyInvocation.MyCommand)] netsh interface ip delete arpcache failed (exit code $($result.ExitCode)): $($result.Output)" } else { Write-Verbose "[$($MyInvocation.MyCommand)] ARP cache cleared successfully" Write-Information -MessageData '[OK] ARP cache cleared successfully' -InformationAction Continue } } catch { Write-Error "[$($MyInvocation.MyCommand)] Failed to clear ARP cache: $_" } } } end { Write-Verbose "[$($MyInvocation.MyCommand)] Completed ARP cache clear operation" } } |