Get DNS Name from IP Address

Get-NameFromIP.ps1 demonstrates two functions which I use frequently:

Function Test-IsIP ($strTest) { 
    [Net.IPAddress]::TryParse($strTest, [ref]$null) 
}

and

Function Get-HostName($IP) {
    Try {
 ([System.Net.DNS]::GetHostByAddress($IP)).hostName 
    }
    Catch {
        Write-Warning "Not resolved"
    }
}

Together these provide you with a good way of testing IP input from user and natively resolving IP addresses to DNS hostnames.