Public/Test-IPv4MaskString.ps1
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function Test-IPv4MaskString { <# .SYNOPSIS Tests whether an IPv4 network mask string (e.g., "255.255.255.0") is valid. .DESCRIPTION Tests whether an IPv4 network mask string (e.g., "255.255.255.0") is valid. .PARAMETER MaskString Specifies the IPv4 network mask string (e.g., "255.255.255.0"). .EXAMPLE Test-IPv4MaskString -MaskString "255.255.255.0" #> [CmdletBinding(ConfirmImpact = 'Medium')] Param ( [Parameter(Mandatory = $false, ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true, ValueFromRemainingArguments = $false, HelpMessage = "Specifies the IPv4 network mask string (e.g., 255.255.255.0)", Position = 1)] [String] $MaskString ) Begin { Write-Verbose -Message '|=> ************************************************************************ <=|' Write-Verbose -Message (Get-Date).ToShortDateString() Write-Verbose -Message (' Starting: {0}' -f $MyInvocation.Mycommand) Write-Verbose -Message ('Parameters used by the function... {0}' -f (Get-FunctionDisplay $PsBoundParameters -Verbose:$False)) } #end Begin Process { $validBytes = '0|128|192|224|240|248|252|254|255' $maskPattern = ('^((({0})\.0\.0\.0)|' -f $validBytes) + ('(255\.({0})\.0\.0)|' -f $validBytes) + ('(255\.255\.({0})\.0)|' -f $validBytes) + ('(255\.255\.255\.({0})))$' -f $validBytes) $MaskString -match $maskPattern } #end Process End { Write-Verbose -Message "Function $($MyInvocation.InvocationName) finished." Write-Verbose -Message '' Write-Verbose -Message '-------------------------------------------------------------------------------' Write-Verbose -Message '' } #end End } #end Function |