How to Rotate MQTT Credentials Without Downtime
A step-by-step dual-credential strategy for rotating MQTT usernames and passwords across a fleet: stage the new credential, switch with fallback, verify and only then revoke the old one.
7 min read
Blog
MQTT Security
Secure your MQTT deployment: TLS, authentication, credentials on devices and protection against abuse, with practical checklists.
MQTT Security
Storing MQTT Credentials Securely on Embedded Devices
A practical comparison of ways to protect MQTT usernames and passwords on ESP32 and Linux devices, from encrypted NVS and flash encryption to secure elements and TPM-backed systemd credentials.
7 min read
SSL Certificate Verify Failed MQTT Error: Fixing Python Clients
Getting "[SSL: CERTIFICATE_VERIFY_FAILED]" when your Python MQTT client connects on port 8883? Here is how to find the exact cause and fix it properly on every platform, without disabling verification.
7 min read
MQTT Access Control Lists (ACLs): Concepts and Design
What MQTT access control lists are, how brokers such as Mosquitto express topic-level read and write rules, how denied operations behave and how to design topic namespaces so authorization stays simple.
7 min read
MQTT Security Best Practices: A 12-Point Checklist for IoT Teams
A hands-on MQTT security checklist covering TLS, credentials, client IDs, topic design, payload validation, rate limits and certificate checks, plus how ConnectMQ handles each point.
11 min read
MQTT mTLS: Mutual TLS with X.509 Client Certificates Explained
Mutual TLS lets an MQTT broker authenticate devices by X.509 certificate. Learn how it works, how to set it up on Mosquitto, what it costs to operate, and when credentials over TLS are the better fit.
7 min read
MQTT TLS Handshake Failed: How to Diagnose and Fix It
A step-by-step troubleshooting guide for MQTT TLS handshake failures, using openssl s_client to pinpoint wrong ports, missing CAs, SNI problems, clock drift, TLS version mismatches and intercepting proxies.
8 min read
Common MQTT Vulnerabilities and How to Mitigate Them
A defender's overview of MQTT vulnerability classes in brokers, clients and deployments, with concrete mitigations and a patching strategy that does not depend on luck.
7 min read
EU Cyber Resilience Act and IoT: What It Means for MQTT Devices
The EU Cyber Resilience Act sets cybersecurity requirements for products with digital elements. Learn what it asks of connected devices and how secure MQTT connectivity supports your work.
8 min read
MQTT TLS 1.3: Handshakes, Cipher Suites and Performance
How TLS 1.3 changes MQTT connections: fewer round trips, a smaller set of strong cipher suites and different trade-offs for microcontrollers. Includes Python, Node.js, Mosquitto and OpenSSL examples.
7 min read
MQTT Audit Logging: What to Record and Why
A practical guide to MQTT audit logging: which events matter for security and compliance, what fields to capture, where logs come from in a managed setup, and how to build a simple pipeline.
7 min read
Exposed MQTT Brokers on the Internet: The Risks of Open Port 1883
Internet scans regularly find MQTT brokers that accept anyone on port 1883. Learn what that exposes, how to audit your own broker and how to keep test data and production data apart.
9 min read
MQTT JWT Authentication: Tokens in the Password Field
A practical explanation of carrying JSON Web Tokens in MQTT CONNECT, how brokers validate them, how to handle expiry and refresh on devices, and when static per-device credentials are the simpler choice.
7 min read
Is MQTT Secure? Threats, Myths and Real Protections
An honest look at MQTT security: what the protocol does and does not protect, the threats that actually hit deployments, common myths, and the layers that make an MQTT system secure in practice.
7 min read
MQTT Wireshark Tutorial: Capture and Analyze MQTT Traffic
Capture your own MQTT traffic with Wireshark, read every packet field on port 1883, and see exactly what TLS on port 8883 protects, using the free broker.connectmq.com test broker.
7 min read
End-to-End MQTT Payload Encryption with AES-GCM
TLS protects MQTT messages in transit, but the broker still sees plaintext. Learn how to add end-to-end MQTT payload encryption with AES-GCM in Python, and how to handle keys, nonces and topics safely.
8 min read
IEC 62443 and MQTT: Securing Industrial Messaging with Zones and Conduits
A practical guide to applying IEC 62443 concepts such as zones, conduits, foundational requirements and security levels to an MQTT architecture with edge gateways and a cloud broker.
8 min read
ESP32 Certificate Pinning and CA Validation for MQTT
Three ways to validate a broker certificate on an ESP32: embed a root CA, use the ESP-IDF certificate bundle, or pin. Learn the trade-offs and get working MQTT code for each.
7 min read
Secure IoT Device Provisioning for MQTT Fleets
How to get a unique, protected MQTT identity onto every device: factory provisioning, claim-certificate and bootstrap flows, per-device credentials and the steps to connect provisioned devices to a managed broker.
7 min read
MQTT Penetration Testing: A Practical Methodology for Your Own Brokers
A structured, defensive approach to MQTT penetration testing: how to scope a test of your own broker, what to check at each layer and how to turn findings into hardening work.
8 min read
MQTT OT Security: Protecting Industrial Plants When Sending Data to the Cloud
How to move data from PLCs and machines to a cloud MQTT broker without opening the plant network: outbound-only design, DMZ patterns, segmentation, credentials and monitoring.
8 min read
MQTT Username and Password Authentication Explained
How usernames and passwords travel in the MQTT CONNECT packet, why they must always be paired with TLS, how brokers reject bad credentials and how to manage per-device credentials on a managed broker.
7 min read
MQTT Rate Limiting and DoS Protection Explained
How MQTT brokers defend against connection floods, publish storms and oversized payloads, what limits a managed broker applies, and how to write clients that respect them.
8 min read
Zero Trust IoT: Applying Zero Trust Principles to MQTT Messaging
Zero trust for IoT means no device or network is trusted by default. Learn how to apply identity, least privilege, encryption and continuous verification to MQTT messaging.
7 min read
MQTT TLS Configuration: A Practical Guide to Port 8883
Learn how MQTT TLS really works, what clients must verify, and how to configure Python, Node.js, ESP32 and mosquitto clients for an encrypted connection on port 8883.
7 min read
Self-Signed Certificate MQTT Setup: When and How to Use One
A hands-on tutorial for building a private certificate authority with OpenSSL, securing a lab Mosquitto broker on port 8883 and connecting clients, plus the operational costs that make public certificates easier in production.
7 min read
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