Check if IP or hostnames are local, with loose restrictions on host name

networktools

  function ipv42long(addr) {
    var octets = addr.split('.')
    return (parseInt(octets[0]) * 16777216) + (parseInt(octets[1]) * 65536) + (parseInt(octets[2]) * 256) + parseInt(octets[3])
  }
  
  function isPrivateIP(addr) {
    var is_private = false,
      ranges = [
        ['10.0.0.0', '10.255.255.255'],
        ['172.16.0.0', '172.31.255.255'],
        ['192.168.0.0', '192.168.255.255'],
        ['169.254.0.0', '169.254.255.255'],
        ['127.0.0.0', '127.255.255.255']
      ], 
      longip = ipv42long(addr)
    if (longip != -1) {
      for (var r=0;r<ranges.length;r++) {
        var range = ranges[r],
          r_s = range[0],
          r_e = range[1]
        if ((longip >= ipv42long(r_s)) && (longip <= ipv42long(r_e))) {
          is_private = true
          break
        }
      }
    }
    return is_private
  }
  
  function isLocalHost(addr) {
    var rx = new RegExp('http(|s)://localhost.*')
    return rx.test(addr)
  }