shadow1ng/fscan · error

i18n.GetText("memcached_connect_failed")

Error message

i18n.GetText("memcached_connect_failed")

What it means

identifyService returns this error when the initial TCP dial to the memcached target fails inside connectToMemcached (dial error or context cancellation). The plugin could not even open a socket, so it reports 'memcached connect failed' instead of a service-identification failure. It surfaces in DisableBrute mode or whenever identifyService runs via Scan.

Source

Thrown at plugins/services/memcached.go:124

	response := make([]byte, 1024)
	n, err := conn.Read(response)
	if err != nil {
		return false
	}

	responseStr := string(response[:n])
	return common.ContainsAny(responseStr, "VERSION", "memcached")
}

func (p *MemcachedPlugin) identifyService(ctx context.Context, info *common.HostInfo, session *common.ScanSession) *ScanResult {
	target := info.Target()

	conn := p.connectToMemcached(ctx, info, session)
	if conn == nil {
		return &ScanResult{
			Success: false,
			Service: "memcached",
			Error:   fmt.Errorf("%s", i18n.GetText("memcached_connect_failed")),
		}
	}
	defer func() { _ = conn.Close() }()

	if p.testBasicCommand(conn, session.Config) {
		banner := "Memcached"
		session.LogSuccess(i18n.Tr("memcached_service", target, banner))
		return &ScanResult{
			Type:    plugins.ResultTypeService,
			Success: true,
			Service: "memcached",
			Banner:  banner,
		}
	}

	return &ScanResult{
		Success: false,
		Service: "memcached",

View on GitHub (pinned to 95cc12e753)

Solutions

1. Confirm the port is open: nc -zv <host> 11211 from the scanning machine.
2. Check for firewalls/iptables/security groups blocking the scanner's source IP.
3. Raise ModuleTimeout in the scan config for high-latency networks.
4. Verify the target address format (host:port) in HostInfo is correct and reachable.
5. Re-run with retries; transient packet loss can fail a single dial attempt.

Example fix

// before
conn := p.connectToMemcached(ctx, info, session)
if conn == nil {
    return &ScanResult{Success: false, Error: fmt.Errorf("%s", i18n.GetText("memcached_connect_failed"))}
}
// after
// caller-side guard: verify reachability and retry once before treating as connect failure
if !isTCPPortOpen(host, 11211, 3*time.Second) {
    log.Printf("skip %s: port 11211 not reachable", host)
    return
}
result := plugin.Scan(ctx, info, session) // retry logic configured via session timeouts

func ensureMemcachedDialable(target string, timeout time.Duration) error {
	conn, err := net.DialTimeout("tcp", target, timeout)
	if err != nil { return fmt.Errorf("cannot reach %s: %w", target, err) }
	_ = conn.Close()
	return nil
}
// call before plugin.Scan
if err := ensureMemcachedDialable("10.0.0.5:11211", 3*time.Second); err != nil { log.Fatal(err) }

func isConnectFailure(r *services.ScanResult) bool {
	return r != nil && !r.Success && r.Error != nil && strings.Contains(r.Error.Error(), "connect")
}

result := plugin.Scan(ctx, info, session)
if !result.Success && isConnectFailure(result) {
	log.Printf("skipping %s: TCP connect failed: %v", info.Target(), result.Error)
	return // do not retry immediately; check network first
}

When it happens

Trigger: Running the memcached plugin (ports 11211-11213) against a host where: the port is closed/filtered; DNS or IP routing fails; ModuleTimeout expires during DialTCP; the parent context is cancelled before the dial completes.

Common situations: Scanning hosts behind a firewall that drops (rather than rejects) packets, causing timeouts; typo'd targets or stale IP lists; scanning through NAT where 11211 is not forwarded; rate-limiting by the target network.

Understand the failure class

Background: ECONNREFUSED and "connection refused" / "could not connect to server" errors: what they mean and how to fix them — this error's family across 44 libraries.

Related errors

• socks5_target_connect_failed: %w
• ms17010_set_timeout_error: %w
• netbios_smb_negotiate_read_failed: %w
• service_connection_failed
• network_rate_limited

AI-assisted analysis of shadow1ng/fscan@95cc12e753 (2026-09-06). Data as JSON: /api/errors/39d9506d975e762c. Report an issue: GitHub.