Introduction:
This article explains how to manage the client certificate prompt that may appear when accessing the Vault UI of your HCP Vault Dedicated cluster when TLS Certificate Authentication is enabled. Unlike self-managed Vault, direct configuration of the Vault server is not accessible in HCP Vault Dedicated. This article outlines the behavior and provides a specific workaround to avoid the UI prompt.
Understanding TLS Certificate Authentication in HCP Vault Dedicated:
HCP Vault Dedicated offers the option to enable TLS Certificate Authentication for secure client access. When this feature is enabled (via a support request), your Vault cluster can authenticate clients based on the TLS certificates they present.
As outlined in the HCP Vault Dedicated Constraints and Limitations Documentation, TLS Certificate Authentication is not enabled by default and requires a support request to activate.
However, when accessing the Vault UI (typically on port 8200) with TLS Certificate Authentication enabled, your web browser might present a popup asking you to select a client certificate. While you can close this popup and still access the UI, it can be an undesirable user experience.
Important Consideration: Cluster-Wide Setting:
It's crucial to understand that TLS Certificate Authentication is a cluster-wide setting in HCP Vault Dedicated. Once enabled, disabling it will completely remove the TLS Certificate Authentication method for the entire Vault cluster, affecting all namespaces.
Workaround to Avoid the Client Certificate Prompt in the UI:
Due to the managed nature of HCP Vault Dedicated, you cannot directly modify the tls_client_auth server configuration as described in articles for self-managed Vault. Instead, the following workaround leverages the availability of an alternate port:
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Disable TLS Certificate Authentication on the default Vault port (8200). To do this, you will need to submit a support request through the designated channel. Clearly state your intention to disable TLS Certificate Authentication on port 8200. Be aware that this will temporarily disable TLS Certificate Authentication on the standard UI access port.
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Submit a new support request to enable TLS Certificate Authentication specifically on port 8207. Inform HashiCorp support that you wish to enable TLS Certificate Authentication on this alternate port.
How this Workaround Functions:
By disabling TLS Certificate Authentication on port 8200 and enabling it on port 8207, you achieve the following:
- Users accessing the Vault UI on the default port 8200 will no longer be prompted for a client certificate. The UI will be accessible without this interruption.
- Applications and other clients that require TLS Certificate Authentication can connect to your Vault cluster on port 8207 and utilize this authentication method.
Implications of this Workaround:
- Any existing clients or applications currently using TLS Certificate Authentication on port 8200 will need to be reconfigured to use port 8207.
- Ensure that your network firewall rules are configured to allow traffic on both port 8200 and port 8207 as needed.
Conclusion:
While direct server configuration to suppress the client certificate prompt in the UI is not available in HCP Vault Dedicated, utilizing the ability to enable TLS Certificate Authentication on a specific port provides an effective workaround. By disabling it on the default UI port (8200) and enabling it on an alternate port (8207), you can provide a seamless UI experience while still leveraging TLS Certificate Authentication for other client interactions.