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Managing Azure Service Bus When TCP Port 5671 Is Blocked

Arvind Narendrakumar

Jun 14, 2021

Category: Azure Service Bus

Problem

Azure Service Bus always requires the use of TLS (Transport Layer Security). It supports connections over TCP port 5671. It requires the port 5671(default port used by AMQP) to be enabled in the network of the sender or receiver local system. Connection to Azure Service Bus will fail if this port is disabled.

Solution (AMQP Over WebSocket)

The AMQP WebSocket Binding defines a mechanism for tunnelling an AMQP connection over a WebSocket transport.  Web Sockets binding creates a tunnel over TCP port 443 that is then equivalent to AMQP 5671 connections. This makes the alternative way or method to transport the messages to the service bus queues and topics.

If theTCP port 5671 (default port used by AMQP) is blocked in the client’s firewall network, then the client cannot receive/peek the sent messages from any of the connected service bus account topics and subscriptions. So we could use AMQP over WebSocket option which could act as an equivalent AMQP connection to peek the messages from the connected service bus queues and topics.

How do we do it in Cerebrata

Cerebrata supports both “AMQP” and “AMQP Over WebSocket” for connecting to Azure Service Bus. By default it uses AMQP. In case port 5671 is blocked, you can easily switch to “AMQP Over WebSocket”. To enable the option in Cerebrata you should navigate to File menu > Settings > Application Settings > Service Bus  Settings > General Settings > Check  the Use AMQP over WebSocket checkbox and click Save.