Public/Network/Test-IsValidIPv4.ps1

function Test-IsValidIPv4 {
  <#
.SYNOPSIS
    Verifies if passed parameter is a valid IP v4 address
.DESCRIPTION
    Verifies if passed parameter is a valid IP v4 address. Can take single string or array of strings.
    Can also accept input from the pipeline. Function aliased to 'Test-IsValidIP'
.EXAMPLE
    Test-IsValidIPv4 '10.0.0.1'
.EXAMPLE
    Test-IsValidIPv4 '10.0.0.1' -Verbose
 
    VERBOSE: The string being tested if a valid IPv4 address is [10.0.0.1]
    True
.EXAMPLE
    '192.168.1.1','invalid' | Test-IsValidIPv4 -IncludeInput
 
    Input Result
    ----- ------
    192.168.1.1 True
    invalid False
#>


  #region Param
  [CmdletBinding(ConfirmImpact = 'None')]
  [Outputtype('bool')]
  [alias('Test-IsValidIP')]
  Param (
    [parameter(ValueFromPipeLine, ValueFromPipeLineByPropertyName)]
    [Alias('IP')]
    [string[]] $IPAddress,
    [switch] $IncludeInput
  )
  #endregion Param

  begin {
    Write-Invocation $MyInvocation
  }

  process {
    foreach ($i in $IPAddress) {
      Try {
        Out-Verbose "The string being tested if a valid IPv4 address is [$i]"
        $check = [ipaddress] $i
        # added check below to cover issue if enter only 3 octets
        # [ipaddress] "10.1.4" resolves to "10.1.0.4"
        if ($i -eq $check) {
          if ($IncludeInput) {
            New-Object -TypeName psobject -Property ([ordered] @{Input = "$i"; Result = $true })
          } else {
            Write-Output -InputObject $true
          }
        } else {
          if ($IncludeInput) {
            New-Object -TypeName psobject -Property ([ordered] @{Input = "$i"; Result = $false })
          } else {
            Write-Output -InputObject $false
          }
        }
      } Catch {
        if ($IncludeInput) {
          New-Object -TypeName psobject -Property ([ordered] @{Input = "$i"; Result = $false })
        } else {
          Write-Output -InputObject $false
        }
      }
    }
  }

  end {
    Out-Verbose $fxn "Complete."
  }
}