util/validation.go
func IsHostname(s string) bool {
	addrs, err := net.LookupHost(s)
	if err != nil || len(addrs) == 0 {
		return false
	}
	return true
}
func IsHostname(s string) bool {
	addrs, err := net.LookupHost(s)
	if err != nil || len(addrs) == 0 {
		return false
	}
	return true
}
// IsHostname checks if this is a hostname