code: func isIPAddrResolvable(fl FieldLevel) bool {
  
  	if !isIP(fl) {
  		return false
  	}
  
  	_, err := net.ResolveIPAddr("ip", fl.Field().String())
  
  	return err == nil
  }
docs: // IsIPAddrResolvable is the validation function for validating if the field's value is a resolvable ip address.