readme.md

References:

• https://geekeefy.wordpress.com/2015/10/24/powershell-resolve-dns-hostname-to-ip-and-reverse-using-a-single-function/
• https://gist.github.com/PrateekKumarSingh/586f2d3d43f7e8cb07ce

Usage:

Resolve-Host (gc .\ips.txt) | ft -auto
Resolve-Host (gc .\ips.txt) | Export-Csv -NoTypeInformation -Path ips-hostnames.csv

Resolve-Host.Ps1

Function Resolve-Host()
{
    Param(
    [Parameter(Mandatory=$true,Position=0)] $HostEntry,
    [Switch] $HostnameToIP,
    [Switch] $FlushDNS
    )
    
    If($FlushDNS)
    {
        Ipconfig /FlushDNS | Out-Null
    }
   
    If($HostnameToIP)
    {
        $object = @()
        $HostEntry | %{
        
        
        $Object += New-Object psobject -Property @{  HostName= $_
                                                     IPAddress=$([System.Net.Dns]::gethostentry($_).AddressList.IPAddressToString)
                                                  }
                      }
        
        Return $object | select Hostname, IPAddress
    }
    else
    {
        $object = @()
        $HostEntry | %{
        
        
        $Object += New-Object psobject -Property @{  IPAddress= $_
                                                     HostName=$([System.Net.Dns]::gethostentry($_).HostName)
                                                  }
                      }
        
        Return $object | select IPAddress, Hostname
    }
}