if host != "" {
			if net.ParseIP(host) != nil {
				ip = host
			} else {
				ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
				defer cancel()

				haddrs, err := globalDNSCache.LookupHost(ctx, host)
				if err == nil {
					ip = haddrs[0]
				}
			}
		}
		ifs, _ := net.Interfaces()
		for _, interf := range ifs {
			addrs, err := interf.Addrs()
			if err == nil {