Functions/Resolve-FQDN.ps1
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function Resolve-FQDN { <# .SYNOPSIS Resolves a hostname or IPv4 address to a fully qualified domain name .DESCRIPTION Resolves a hostname or IPv4 address to a fully qualified domain name .PARAMETER ComputerName Either the hostname or IPv4 address of the computer you want resolved to FQDN. Aliased to 'CN', and 'Host' .PARAMETER IncludeInput Switch to include the input parameters in the output .EXAMPLE Resolve-FQDN -ComputerName $env:computername Display the FQDN of this computer .EXAMPLE Resolve-FQDN -ComputerName '10.28.99.101' Display the FQDN of the computer whose IPv4 address is 10.28.99.101 .EXAMPLE Resolve-FQDN . Display the FQDN of this computer .EXAMPLE '10.28.99.101' | Resolve-FQDN Display the FQDN of the computer whose IPv4 address is 10.28.99.101 .EXAMPLE $DomainController = (($env:logonserver).Substring(2)) Resolve-FQDN $DomainController Display the FQDN of the Active Directory Domain Controller that you authenticated against when you logged onto Windows. .EXAMPLE PS C:\> Resolve-FQDN -ComputerName "NonExistentPC" The computer "NonExistentPC" does not have an entry in DNS so the function will return the value $False .NOTES Attempting to resolve a FQDN for a system that does not have an entry in DNS will be slow, and will take 1-5 seconds to return a value of $False #> [CmdletBinding()] Param ( [parameter(ValueFromPipeLine, ValueFromPipeLineByPropertyName, Mandatory)] [Alias('Host', 'CN', 'Server')] [string[]] $ComputerName, [switch] $IncludeInput ) begin { Write-Verbose -Message "Starting [$($MyInvocation.Mycommand)]" } process { foreach ($curComputer in $ComputerName) { if ($curComputer -eq '.') { $curComputer = $env:COMPUTERNAME } $curComputer = $curComputer.ToLower() try { $FQDN = [System.Net.Dns]::GetHostEntry($curComputer).HostName $FQDN = $FQDN.ToLower() #Write-Output -InputObject $FQDN } catch { $FQDN = 'Not found' #Write-Output -InputObject $False } if ($IncludeInput) { New-Object -TypeName psobject -Property ([ordered] @{ HostName = $curComputer FQDN = $FQDN }) } else { Write-Output -InputObject $FQDN } } } end { Write-Verbose -Message "Ending [$($MyInvocation.Mycommand)]" } } |