OCSP Client & Driver Configuration

Snowflake uses Online Certificate Status Protocol (OCSP) to provide maximum security to determine whether a certificate is revoked when Snowflake clients attempt to connect to an endpoint through HTTPS.

Snowflake uses OCSP to evaluate each certificate in the chain of trust up to the intermediate certificate the root certificate authority (CA) issues. Ensuring that each certificate is not revoked helps Snowflake to establish secure connections with trusted actors during the identity verification process.

Depending on your client or driver version and the configuration described on this page, it is possible to turn off OCSP and to adjust the action that occurs when OCSP determines a certificate is revoked.

Fail-Open or Fail-Close Behavior

Currently, users can choose between either of two behaviors in terms of how Snowflake clients or drivers respond during an OCSP event.

  1. Fail-open
  2. Fail-close


Snowflake supports a fail-open approach by default in terms of evaluating the OCSP CA response. The fail-open approach has the following characteristics:

  • A response indicating a revoked certificate results in a failed connection.
  • A response with any other certificate errors or statuses allows the connection to occur, but denotes the message in the logs at the WARNING level with the relevant details in JSON format.

Users can monitor the logs for the specific driver or connector to determine the frequency of fail-open log events.

These event logs can be combined with the Snowflake Status Page to determine the best course of action, such as temporarily restricting client access or pivoting to fail-close behavior.

Currently, the fail-open default approach applies to the following client and driver versions.

Client / Driver Version
SnowSQL v1.1.79 or later
Python Connector v1.8.0 or later
JDBC Driver v3.8.0 or later
ODBC Driver v2.19.0 or later
SQL Alchemy Upgrade Python Connector to v1.8.0 or later
Spark v2.4.14 or later if using Maven or SBT to build the Spark application. . JDBC v3.8.0 or later if attaching JAR files to Spark cluster. . Request Databricks to upgrade their Spark connector if using the Databricks built-in Spark connector.


Snowflake does not support OCSP checking for the .NET driver. Instead, .NET uses its own framework to check the validity of the HTTPS certificate.


The fail-close behavior is more restrictive to interpreting the OCSP CA response. If the client or driver does not receive a valid OCSP CA response for any reason, the connection fails.

Since this behavior is not default based on the versions listed in the fail-open section, fail-close must be configured manually within each driver or connector.

To preserve the fail-close behavior, set the corresponding ocsp_fail_open parameter to false.

Client / Driver Setting
SnowSQL snowsql -o ocsp_fail_open=false
Python Connector Set the connection parameter to ocsp_fail_open=false
JDBC Driver Choose one of the following: . Set the connection property to ocspFailOpen=false . Set the system property to net.snowflake.jdbc.ocspFailOpen=false
ODBC Driver Choose one of the following: . Set the connection parameter to OCSP_FAIL_OPEN=false . Use the environment variable $SIMBAINI to locate the corresponding file. Then set OCSPFailOpen=false
SQL Alchemy See JDBC Driver settings
Spark The Spark Connector does not have an ocsp_fail_open parameter. . Fail-close can only be preserved with Spark if using the JDBC driver.

Legacy Client & Driver Versions

If your client or driver version is older than that listed in the fail-open section, the fail-open behavior is not an option. Therefore, the fail-close behavior is default.

Snowflake deployments using legacy client and driver versions with respect to OCSP have three options:

  1. Upgrade their client or driver to its latest version (best option).
  2. Continue using the fail-close behavior.
  3. Turn off OCSP monitoring (i.e., insecure mode) as described here.

Best Practices

To mitigate risk, Snowflake recommends the following best practices to keep communications secure.

  1. Use AWS PrivateLink and block public access to Snowflake.
  2. Allow client drivers to run on managed desktops and servers only.
  3. Send client driver logs to a management system or upload to Snowflake. Monitor the connections made without OCSP checking.


Support for AWS PrivateLink requires ESD (or higher). To inquire about upgrading, please contact Snowflake Support.