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panksume's avatar
panksume
Copper Contributor
Sep 10, 2025

ADF connection issue with Cassandra

Hi,  I am trying to connect a cassandra DB hosted in azure cosmos db. I created the linked service but getting below error on test connection.  Already checked the cassandra DB and its public netwo...
azure data factory
Azure Data Integration
Azure Integration Runtime
Mageee's avatar
Mageee
Brass Contributor
Sep 20, 2025

This usually happens because Azure Cosmos DB Cassandra API requires a secure connection (TLS/SSL) and the correct port. In ADF, the linked service doesn’t expose a simple “Enable SSL” toggle, but you can work around it:

Make sure you’re using the right port – Cosmos DB Cassandra API expects 10350 (not the default 9042).

In the linked service, the connection string needs to specify EnableSsl=true (sometimes you have to include it in the “additional connection properties” field).

Double-check that you’re using the username and password from Cosmos DB Keys (not a local Cassandra login).

Ensure your firewall/network rules allow outbound traffic on that port. Even though “All networks” is enabled, ADF still needs outbound reachability.

A lot of people hit this when ADF defaults to plain Cassandra settings. Adding SSL and the correct port usually fixes it.