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) #display PSBoundparameters formatted nicely for Verbose output $NL = "`n" # New Line $HTab = "`t" # Horizontal Tab [string]$pb = ($PSBoundParameters | Format-Table -AutoSize | Out-String).TrimEnd() Write-Verbose -Message "Parameters used by the function... $NL$($pb.split($NL).Foreach({"$($HTab*4)$_"}) | Out-String) $NL" } 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 { Write-Verbose -Message "Function $($MyInvocation.InvocationName) finished." Write-Verbose -Message '' Write-Verbose -Message '-------------------------------------------------------------------------------' Write-Verbose -Message '' } } |