title: What is *.servicebus.windows.net used for in Azure Data Factory?
body: <p>In a hybrid scenario with self-hosted integration runtime installed to connect to on-premises database, and firewall allowing outbound port 443 *.frontend.clouddatahub.net which according to <a href="https://docs.microsoft.com/en-us/azure/data-factory/data-movement-security-considerations" rel="nofollow noreferrer">docs</a> is <em>Required by the self-hosted integration runtime to connect to the Data Factory service</em>.</p>
  
  <p>The integration runtime is able to connect to Azure Data Factory with status <em>Running (Limited)</em> and a warning saying that the cloud service cannot connect to the integration runtime through Service Bus.</p>
  
  <p>The same <a href="https://docs.microsoft.com/en-us/azure/data-factory/data-movement-security-considerations" rel="nofollow noreferrer">docs</a> say that outbound port 443 *.servicebus.windows.net is <em>Required by the self-hosted integration runtime to connect to data movement services in Azure Data Factory</em>. If I understand correctly this includes copying data to the on-premises database and therefore is required.</p>
  
  <p>What exactly is Service Bus used for in Azure Data Factory, and preferably from the integration runtime perspective? The figure for Hybrid scenarios shows <em>Command Channel</em> and <em>Data Channel</em>. Does the latter represent data sent over Service Bus?</p>
  
  <p>Any insight will be appreciated. Thanks for your consideration and have a nice day!</p>