C#

public static IEnumerable<IPAddress> ParseIPAddressRange(string inputString)
{
  string[] tokens = inputString.Split('.');
  foreach (IPAddress addr in ParseIPAddressRange(tokens, 0, string.Empty))
    yield return addr;
}
private static IEnumerable<IPAddress> ParseIPAddressRange(string[] tokens, int index, string partial)
{
  if (index > 3)
    yield return IPAddress.Parse(partial);
  else if (index >= tokens.Length || tokens[index] == "*")
  {
    for (int x = 0; x < 256; x++)
      foreach (IPAddress addr in ParseIPAddressRange(tokens, index + 1, partial + "." + x.ToString()))
        yield return addr;
  }
  else
  {
    // Parse out tokens[index], append it to partial and recurse like above
    // This is just an exercise in string parsing... Easy.
  }
}