SSL/TLS connection issue troubleshooting guide
You may experience exceptions or errors when establishing TLS connections with Azure services. Exceptions are vary dramatically depending on the client and server types. A typical ones such as "Could not create SSL/TLS secure channel." "SSL Handshake Failed", etc. In this article we will discuss common causes of TLS related issue and troubleshooting steps.JSON Structure: A JSON schema language you'll love
We talk to many customers moving structured data through queues and event streams and topics, and we see a strong desire to create more efficient and less brittle communication paths governed by rich data definitions well understood by all parties. The way those definitions are often shared are schema documents. While there is great need, the available schema options and related tool chains are often not great. JSON Schema is popular for its relative simplicity in trivial cases, but quickly becomes unmanageable as users employ more complex constructs. The industry has largely settled on "Draft 7," with subsequent releases seeing weak adoption. There's substantial frustration among developers who try to use JSON Schema for code generation or database mapping—scenarios it was never designed for. JSON Schema is a powerful document validation tool, but it is not a data definition language. We believe it's effectively un-toolable for anything beyond pure validation; practically all available code-generation tools agree by failing at various degrees of complexity. Avro and Protobuf schemas are better for code generation, but tightly coupled to their respective serialization frameworks. For our own work in Microsoft Fabric, we're initially leaning on an Avro-compatible schema with a small set of modifications, but we ultimately need a richer type definition language that ideally builds on people's familiarity with JSON Schema. This isn't just a Microsoft problem. It's an industry-wide gap. That's why we've submitted JSON Structure as a set of Internet Drafts to the IETF, aiming for formal standardization as an RFC. We want a vendor-neutral, standards-track schema language that the entire industry can adopt. What Is JSON Structure? JSON Structure is a modern, strictly typed data definition language that describes JSON-encoded data such that mapping to and from programming languages and databases becomes straightforward. It looks familiar—if you've written "type": "object", "properties": {...} before, you'll feel right at home. But there's a key difference: JSON Structure is designed for code generation and data interchange first, with validation as an optional layer rather than the core concern. This means you get: Precise numeric types: int32 , int64 , decimal with precision and scale, float , double Rich date/time support: date , time , datetime , duration —all with clear semantics Extended compound types: Beyond objects and arrays, you get set , map , tuple , and choice (discriminated unions) Namespaces and modular imports: Organize your schemas like code Currency and unit annotations: Mark a decimal as USD or a double as kilograms Here's a compact example that showcases these features. We start with the schema header and the object definition: { "$schema": "https://json-structure.org/meta/extended/v0/#", "$id": "https://example.com/schemas/OrderEvent.json", "name": "OrderEvent", "type": "object", "properties": { Objects require a name for clean code generation. The $schema points to the JSON Structure meta-schema, and the $id provides a unique identifier for the schema itself. Now let's define the first few properties—identifiers and a timestamp: "orderId": { "type": "uuid" }, "customerId": { "type": "uuid" }, "timestamp": { "type": "datetime" }, The native uuid type maps directly to Guid in .NET, UUID in Java, and uuid in Python. The datetime type uses RFC3339 encoding and becomes DateTimeOffset in .NET, datetime in Python, or Date in JavaScript. No format strings, no guessing. Next comes the order status, modeled as a discriminated union: "status": { "type": "choice", "choices": { "pending": { "type": "null" }, "shipped": { "type": "object", "name": "ShippedInfo", "properties": { "carrier": { "type": "string" }, "trackingId": { "type": "string" } } }, "delivered": { "type": "object", "name": "DeliveredInfo", "properties": { "signedBy": { "type": "string" } } } } }, The choice type is a discriminated union with typed payloads per case. Each variant can carry its own structured data— shipped includes carrier and tracking information, delivered captures who signed for the package, and pending carries no payload at all. This maps to enums with associated values in Swift, sealed classes in Kotlin, or tagged unions in Rust. For monetary values, we use precise decimals: "total": { "type": "decimal", "precision": 12, "scale": 2 }, "currency": { "type": "string", "maxLength": 3 }, The decimal type with explicit precision and scale ensures exact monetary math—no floating-point surprises. A precision of 12 with scale 2 gives you up to 10 digits before the decimal point and exactly 2 after. Line items use an array of tuples for compact, positional data: "items": { "type": "array", "items": { "type": "tuple", "properties": { "sku": { "type": "string" }, "quantity": { "type": "int32" }, "unitPrice": { "type": "decimal", "precision": 10, "scale": 2 } }, "tuple": ["sku", "quantity", "unitPrice"], "required": ["sku", "quantity", "unitPrice"] } }, Tuples are fixed-length typed sequences—ideal for time-series data or line items where position matters. The tuple array specifies the exact order: SKU at position 0, quantity at 1, unit price at 2. The int32 type maps to int in all mainstream languages. Finally, we add extensible metadata using set and map types: "tags": { "type": "set", "items": { "type": "string" } }, "metadata": { "type": "map", "values": { "type": "string" } } }, "required": ["orderId", "customerId", "timestamp", "status", "total", "currency", "items"] } The set type represents unordered, unique elements—perfect for tags. The map type provides string keys with typed values, ideal for extensible key-value metadata without polluting the main schema. Here's what a valid instance of this schema looks like: { "orderId": "f47ac10b-58cc-4372-a567-0e02b2c3d479", "customerId": "7c9e6679-7425-40de-944b-e07fc1f90ae7", "timestamp": "2025-01-15T14:30:00Z", "status": { "shipped": { "carrier": "Litware", "trackingId": "794644790323" } }, "total": "129.97", "currency": "USD", "items": [ ["SKU-1234", 2, "49.99"], ["SKU-5678", 1, "29.99"] ], "tags": ["priority", "gift-wrap"], "metadata": { "source": "web", "campaign": "summer-sale" } } Notice how the choice is encoded as an object with a single key indicating the active case— {"shipped": {...}} —making it easy to parse and route. Tuples serialize as JSON arrays in the declared order. Decimals are encoded as strings to preserve precision across all platforms. Why Does This Matter for Messaging? When you're pushing events through Service Bus, Event Hubs, or Event Grid, schema clarity is everything. Your producers and consumers often live in different codebases, different languages, different teams. A schema that generates clean C# classes, clean Python dataclasses, and clean TypeScript interfaces—from the same source—is not a luxury. It's a requirement. JSON Structure's type system was designed with this polyglot reality in mind. The extended primitive types map directly to what languages actually have. A datetime is a DateTimeOffset in .NET, a datetime in Python, a Date in JavaScript. No more guessing whether that "string with format date-time" will parse correctly on the other side. SDKs Available Now We've built SDKs for the languages you're using today: TypeScript, Python, .NET, Java, Go, Rust, Ruby, Perl, PHP, Swift, and C. All SDKs validate both schemas and instances against schemas. A VS Code extension provides IntelliSense and inline diagnostics. Code and Schema Generation with Structurize Beyond validation, you often need to generate code or database schemas from your type definitions. The Structurize tool converts JSON Structure schemas into SQL DDL for various database dialects, as well as self-serializing classes for multiple programming languages. It can also convert between JSON Structure and other schema formats like Avro, Protobuf, and JSON Schema. Here's a simple example: a postal address schema on the left, and the SQL Server table definition generated by running structurize struct2sql postaladdress.json --dialect sqlserver on the right: JSON Structure Schema Generated SQL Server DDL { "$schema": "https://json-structure.org/meta/extended/v0/#", "$id": "https://example.com/schemas/PostalAddress.json", "name": "PostalAddress", "description": "A postal address for shipping or billing", "type": "object", "properties": { "id": { "type": "uuid", "description": "Unique identifier for the address" }, "street": { "type": "string", "description": "Street address with house number" }, "city": { "type": "string", "description": "City or municipality" }, "state": { "type": "string", "description": "State, province, or region" }, "postalCode": { "type": "string", "description": "ZIP or postal code" }, "country": { "type": "string", "description": "ISO 3166-1 alpha-2 country code" }, "createdAt": { "type": "datetime", "description": "When the address was created" } }, "required": ["id", "street", "city", "postalCode", "country"] } CREATE TABLE [PostalAddress] ( [id] UNIQUEIDENTIFIER, [street] NVARCHAR(200), [city] NVARCHAR(100), [state] NVARCHAR(50), [postalCode] NVARCHAR(20), [country] NVARCHAR(2), [createdAt] DATETIME2, PRIMARY KEY ([id], [street], [city], [postalCode], [country]) ); EXEC sp_addextendedproperty 'MS_Description', 'A postal address for shipping or billing', 'SCHEMA', 'dbo', 'TABLE', 'PostalAddress'; EXEC sp_addextendedproperty 'MS_Description', 'Unique identifier for the address', 'SCHEMA', 'dbo', 'TABLE', 'PostalAddress', 'COLUMN', 'id'; EXEC sp_addextendedproperty 'MS_Description', 'Street address with house number', 'SCHEMA', 'dbo', 'TABLE', 'PostalAddress', 'COLUMN', 'street'; -- ... additional column descriptions The uuid type maps to UNIQUEIDENTIFIER , datetime becomes DATETIME2 , and the schema's description fields are preserved as SQL Server extended properties. The tool supports PostgreSQL, MySQL, SQLite, and other dialects as well. Mind that all this code is provided "as-is" and is in a "draft" state just like the specification set. Feel encouraged to provide feedback and ideas in the GitHub repos for the specifications and SDKs at https://github.com/json-structure/ Learn More We've submitted JSON Structure as a set of Internet Drafts to the IETF, aiming for formal standardization as an RFC. This is an industry-wide issue, and we believe the solution needs to be a vendor-neutral standard. You can track the drafts at the IETF Datatracker. Main site: json-structure.org Primer: JSON Structure Primer Core specification: JSON Structure Core Extensions: Import | Validation | Alternate Names | Units | Composition IETF Drafts: IETF Datatracker GitHub: github.com/json-structureService Bus - duplicate detection for partitioned messaging entity
Pre-requirements: Before we start, please read these document about Duplicate Detection, Partitioned queues and topics and Message Sessions From the above Pre-requirements, we learn the followings Enabling Duplicate detection helps to ensure that a duplicate message, which has the same message Id cannot be sent into a messaging entity during a specified time. Service Bus Partitions enable queues and topics or message entities to be partitioned across multiple message brokers and messaging stores. Enable partitioning the overall throughput will separate to different partition. Partition key can be used in some scenarios, such as sessions or transactions, require messages to be stored in a specific partition. Microsoft Service Bus Session enable joint and ordered handling of unbounded sequences of messages. There are two patterns of it , first out and request-response pattern. Any sender can create a session when submitting messages into a topic or queue by setting the SessionId property to some application-defined identifier that is unique to the session. So, from these above knowledges, we know that Azure Service Bus Queue and Topic/Subscription can enable for Duplicate Detection, Partitions and Sessions. But what’s the relationship between them?
Azure Service Bus | Receive Messages from DLQ for Queue/Subscription
Azure Service Bus queues and topic subscriptions provide a secondary subqueue, called a dead-letter queue(DLQ). The dead-letter queue need not to be explicitly created and can't be deleted or otherwise managed independent of the main entity. Azure Service Bus messaging overview - Azure Service Bus | Microsoft Docs Messages that can't be processed because of various reasons fall into DLQ. Below are few conditions where messages will fall into DLQ: 1. Not matching with the filter condition 2. TTL expired, header exceed 3. Quota exceed for header size 4. Max delivery count reached 5. Session enabled and sending messages without sessionID 6. Using more than 4 forward to Case: To receive DLQ messages from queue/subscription Pre-Requisites: 1. Service Bus namespace 2. Already created queue/subscription 3. Should have messages in DLQ either for queue/subscription 4. Service Bus Explorer We have multiple ways to receive messages from DLQ. Using Service Bus Explorer: Download the “Service Bus Explorer” from: https://github.com/paolosalvatori/ServiceBusExplorer Open service bus explorer and click File and connect it. From the drop down, select connection string and provide the connection string of the namespace level. Once it is successfully connected, you will see Service Bus Explorer shows the count of the DLQ message. In the below screenshot, there are 11 messages currently in the DLQ for the queue "ankitatest". To receive messages from DLQ through SB explorer, you need to click on that particular queue and then click on “Deadletter” tab then one dialogue box will pop up then you need to click on “Receive and Delete”. The default value is Top10 so top10 messages will be received from DLQ. The updated DLQ message count is now 1. Through C# Code: In the given screenshot, we have 12 messages in DLQ for queue and we wanted to receive them. I will run the below code which will receive the message from the mentioned queue. Once you run the code successfully, you will see the message ID in the console window as below. Now, check on SB explorer and you will see 1 message has been gone from DLQ. class Program { static void Main(string[] args) { RetrieveMessageFromDeadLetterForQueue(); RetrieveMessageFromDeadLetterForSubscription(); } public static void RetrieveMessageFromDeadLetterForQueue() { var receiverFactory = MessagingFactory.Create( "sb://<ServiceBusNamespaceName>.servicebus.windows.net/", new MessagingFactorySettings { TokenProvider = TokenProvider.CreateSharedAccessSignatureTokenProvider("RootManageSharedAccessKey", "<NamespaceLevelKey>"), NetMessagingTransportSettings = { BatchFlushInterval = new TimeSpan(0, 0, 0) } }); string data = QueueClient.FormatDeadLetterPath("<QueueName>"); var receiver = receiverFactory.CreateMessageReceiver(data); receiver.OnMessageAsync( async message => { var body = message.GetBody<Stream>(); lock (Console.Out) { Console.WriteLine(message.MessageId); } await message.CompleteAsync(); }, new OnMessageOptions { AutoComplete = false, MaxConcurrentCalls = 1 }); } public static void RetrieveMessageFromDeadLetterForSubscription() { var receiverFactory = MessagingFactory.Create( "sb://<NS>.servicebus.windows.net/", new MessagingFactorySettings { TokenProvider = TokenProvider.CreateSharedAccessSignatureTokenProvider("RootManageSharedAccessKey", "<NamespaceLevelSASKey>"), NetMessagingTransportSettings = { BatchFlushInterval = new TimeSpan(0, 0, 0) } }); string data = SubscriptionClient.FormatDeadLetterPath("<TopicName>", "<SubscriptionName>"); var receiver = receiverFactory.CreateMessageReceiver(data); receiver.OnMessageAsync( async message => { var body = message.GetBody<Stream>(); lock (Console.Out) { Console.WriteLine("Message ID :" + message.MessageId); } await message.CompleteAsync(); }, new OnMessageOptions { AutoComplete = false, MaxConcurrentCalls = 1 }); } }
Common causes of SSL/TLS connection issues and solutions
In the TLS connection common causes and troubleshooting guide (microsoft.com) and TLS connection common causes and troubleshooting guide (microsoft.com), the mechanism of establishing SSL/TLS and tools to troubleshoot SSL/TLS connection were introduced. In this article, I would like to introduce 3 common issues that may occur when establishing SSL/TLS connection and corresponding solutions for windows, Linux, .NET and Java. TLS version mismatch Cipher suite mismatch TLS certificate is not trusted TLS version mismatch Before we jump into solutions, let me introduce how TLS version is determined. As the dataflow introduced in the first session(https://techcommunity.microsoft.com/t5/azure-paas-blog/ssl-tls-connection-issue-troubleshooting-guide/ba-p/2108065), TLS connection is always started from client end, so it is client proposes a TLS version and server only finds out if server itself supports the client's TLS version. If the server supports the TLS version, then they can continue the conversation, if server does not support, the conversation is ended. Detection You may test with the tools introduced in this blog(TLS connection common causes and troubleshooting guide (microsoft.com)) to verify if TLS connection issue was caused by TLS version mismatch. If capturing network packet, you can also view TLS version specified in Client Hello. If connection terminated without Server Hello, it could be either TLS version mismatch or Ciphersuite mismatch. Solution Different types of clients have their own mechanism to determine TLS version. For example, Web browsers - IE, Edge, Chrome, Firefox have their own set of TLS versions. Applications have their own library to define TLS version. Operating system level like windows also supports to define TLS version. Web browser In the latest Edge and Chrome, TLS 1.0 and TLS 1.1 are deprecated. TLS 1.2 is the default TLS version for these 2 browsers. Below are the steps of setting TLS version in Internet Explorer and Firefox and are working in Window 10. Internet Explorer Search Internet Options Find the setting in the Advanced tab. Firefox Open Firefox, type about:config in the address bar. Type tls in the search bar, find the setting of security.tls.version.min and security.tls.version.max. The value is the range of supported tls version. 1 is for tls 1.0, 2 is for tls 1.1, 3 is for tls 1.2, 4 is for tls 1.3. Windows System Different windows OS versions have different default TLS versions. The default TLS version can be override by adding/editing DWORD registry values ‘Enabled’ and ‘DisabledByDefault’. These registry values are configured separately for the protocol client and server roles under the registry subkeys named using the following format: <SSL/TLS/DTLS> <major version number>.<minor version number><Client\Server> For example, below is the registry paths with version-specific subkeys: Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client For the details, please refer to Transport Layer Security (TLS) registry settings | Microsoft Learn. Application that running with .NET framework The application uses OS level configuration by default. For a quick test for http requests, you can add the below line to specify the TLS version in your application before TLS connection is established. To be on a safer end, you may define it in the beginning of the project. ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 Above can be used as a quick test to verify the problem, it is always recommended to follow below document for best practices. https://docs.microsoft.com/en-us/dotnet/framework/network-programming/tls Java Application For the Java application which uses Apache HttpClient to communicate with HTTP server, you may check link How to Set TLS Version in Apache HttpClient | Baeldung about how to set TLS version in code. Cipher suite mismatch Like TLS version mismatch, CipherSuite mismatch can also be tested with the tools that introduced in previous article. Detection In the network packet, the connection is terminated after Client Hello, so if you do not see a Server Hello packet, that indicates either TLS version mismatch or ciphersuite mismatch. If server is supported public access, you can also test using SSLLab(https://www.ssllabs.com/ssltest/analyze.html) to detect all supported CipherSuite. Solution From the process of establishing SSL/TLS connections, the server has final decision of choosing which CipherSuite in the communication. Different Windows OS versions support different TLS CipherSuite and priority order. For the supported CipherSuite, please refer to Cipher Suites in TLS/SSL (Schannel SSP) - Win32 apps | Microsoft Learn for details. If a service is hosted in Windows OS. the default order could be override by below group policy to affect the logic of choosing CipherSuite to communicate. The steps are working in the Windows Server 2019. Edit group policy -> Computer Configuration > Administrative Templates > Network > SSL Configuration Settings -> SSL Cipher Suite Order. Enable the configured with the priority list for all cipher suites you want. The CipherSuites can be manipulated by command as well. Please refer to TLS Module | Microsoft Learn for details. TLS certificate is not trusted Detection Access the url from web browser. It does not matter if the page can be loaded or not. Before loading anything from the remote server, web browser tries to establish TLS connection. If you see the error below returned, it means certificate is not trusted on current machine. Solution To resolve this issue, we need to add the CA certificate into client trusted root store. The CA certificate can be got from web browser. Click warning icon -> the warning of ‘isn’t secure’ in the browser. Click ‘show certificate’ button. Export the certificate. Import the exported crt file into client system. Windows Manage computer certificates. Trusted Root Certification Authorities -> Certificates -> All Tasks -> Import. Select the exported crt file with other default setting. Ubuntu Below command is used to check current trust CA information in the system. awk -v cmd='openssl x509 -noout -subject' ' /BEGIN/{close(cmd)};{print | cmd}' < /etc/ssl/certs/ca-certificates.crt If you did not see desired CA in the result, the commands below are used to add new CA certificates. $ sudo cp <exported crt file> /usr/local/share/ca-certificates $ sudo update-ca-certificates RedHat/CentOS Below command is used to check current trust CA information in the system. awk -v cmd='openssl x509 -noout -subject' ' /BEGIN/{close(cmd)};{print | cmd}' < /etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem If you did not see desired CA in the result, the commands below are used to add new CA certificates. sudo cp <exported crt file> /etc/pki/ca-trust/source/anchors/ sudo update-ca-trust Java The JVM uses a trust store which contains certificates of well-known certification authorities. The trust store on the machine may not contain the new certificates that we recently started using. If this is the case, then the Java application would receive SSL failures when trying to access the storage endpoint. The errors would look like the following: Exception in thread "main" java.lang.RuntimeException: javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target at org.example.App.main(App.java:54) Caused by: javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target at java.base/sun.security.ssl.Alert.createSSLException(Alert.java:130) at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:371) at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:314) at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:309) Run the below command to import the crt file to JVM cert store. The command is working in the JDK 19.0.2. keytool -importcert -alias <alias> -keystore "<JAVA_HOME>/lib/security/cacerts" -storepass changeit -file <crt_file> Below command is used to export current certificates information in the JVM cert store. keytool -keystore " <JAVA_HOME>\lib\security\cacerts" -list -storepass changeit > cert.txt The certificate will be displayed in the cert.txt file if it was imported successfully.Announcing General Availability of Geo-Replication for Azure Service Bus Premium
Today we are excited to announce general availability of the Geo-Replication feature for Azure Service Bus in the premium tier. This feature ensures that the metadata and data of a namespace are continuously replicated from a primary region to a secondary region. Moreover, this feature allows promoting a secondary region at any time. The Geo-Replication feature is the latest option to insulate Azure Service Bus applications against outages and disasters. Other options are Geo-Disaster Recovery and Availability Zones. Differentiation There are currently two features that provide Geo-Disaster Recovery in Azure Service Bus for the Premium tier. First, there is Geo-Disaster Recovery (Metadata DR) that just provides replication of metadata. Second, Geo-Replication, which is now GA, provides replication of both metadata and data. Neither Geo-Disaster Recovery feature should be confused with Availability Zones. Regardless of if it is Metadata DR or Geo replication, both geographic recovery features provide resilience between Azure regions such as East US and West US. Availability Zones are available on all Service Bus tiers, and support provides resilience within a specific geographic region, such as East US. For a detailed discussion of disaster recovery in Microsoft Azure, see this article. Concepts The Geo-Replication feature implements metadata and data replication in a primary-secondary replication model. It works with a single namespace, and at a given time there’s only one primary region, which is serving both producers and consumers. There is a single hostname used to connect to the namespace, which always points to the current primary region. After promoting a secondary region, the hostname points to the new primary region, and the old primary region is demoted to secondary region. After the new secondary has been re-initialized, it is possible to promote this region again to primary at any moment. Replication modes There are two replication modes, synchronous and asynchronous. It's important to know the differences between the two modes. Asynchronous replication Using asynchronous replication, all requests are committed on the primary, after which an acknowledgment is sent to the client. Replication to the secondary regions happens asynchronously. Users can configure the maximum acceptable amount of lag time, the offset between the latest action on the primary and the secondary regions. If the lag for an active secondary grows beyond user configuration, the primary will throttle incoming requests. Synchronous replication Using synchronous replication, all requests are replicated to the secondary, which must commit and confirm the operation before committing on the primary. As such, your application publishes at the rate it takes to publish, replicate, acknowledge, and commit. Moreover, it also means that your application is tied to the availability of both regions. If the secondary region goes down, messages aren't acknowledged and committed, and the primary will throttle incoming requests. Promotion The customer is in control of promoting a secondary region, providing full ownership and visibility for outage resolution. When choosing Planned promotion, the service waits to catch up the replication lag before initiating the promotion. On the other hand, when choosing Forced promotion, the service immediately initiates the promotion. Pricing The Premium tier for Service Bus is priced per Messaging Unit. With the Geo-Replication feature, secondary regions run on the same number of MUs as the primary region, and the pricing is calculated over the total number of MUs. Additionally, there is a charge for based on the published bandwidth times the number of secondary regions. More information on this feature can be found in the documentation.
