PowerShellで名前解決して返すやつ

DnsResolver.ps1

function Dns-Resolver([String]$domain, [int]$type) {
  Add-Type -AssemblyName System.Net
  [array]$HostEntries = [System.Net.DNS]::GetHostEntry($domain)

  switch($type){
    4 {
      [array]$IPaddresses = $HostEntries.AddressList | ?{$_.AddressFamily -eq "InterNetwork"}
    }
    6 {
      [array]$IPaddresses = $HostEntries.AddressList | ?{$_.AddressFamily -eq "InterNetworkV6"}
    }
  }
  return ($IPaddresses[0]).IPAddressToString
}

# 使い方
# Dns-Resolver ドメイン名 IPアドレスバージョン
# Dns-Resolver gist.github.com 4 ← GithubGistのIPv4アドレスが返ってくる
# Dns-Resolver www.google.co.jp 6 ← GoogleのIPv6アドレスが返ってくる