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(SupportsShouldProcess = $true, ConfirmImpact = 'Low')] [OutputType([bool])] Param ( [Parameter(Mandatory = $false, ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true, ValueFromRemainingArguments = $true, HelpMessage = 'Specifies the IPv4 network mask string (e.g., 255.255.255.0)', Position = 1)] [String] $MaskString ) Begin { $txt = ($Variables.Header -f (Get-Date).ToShortDateString(), $MyInvocation.Mycommand, (Get-FunctionDisplay -HashTable $PsBoundParameters -Verbose:$False) ) Write-Verbose -Message $txt ############################## # Module imports } #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 { $txt = ($Variables.Footer -f $MyInvocation.InvocationName, 'testing whether an IPv4 network mask string.' ) Write-Verbose -Message $txt } #end End } #end Function |