code: func (fp *ForwardProxy) connectPortIsAllowed(port string) bool {
  	portInt, err := strconv.Atoi(port)
  	if err != nil {
  		return false
  	}
  	if portInt <= 0 || portInt > 65535 {
  		return false
  	}
  	if len(fp.whitelistedPorts) == 0 {
  		return true
  	}
  	isAllowed := false
  	for _, p := range fp.whitelistedPorts {
  		if p == portInt {
  			isAllowed = true
  			break
  		}
  	}
  	return isAllowed
  }
docs: // TODO?: getStatusCode(err) that casts to http.Error, net Error, etc. and returns correct http status code