> For the complete documentation index, see [llms.txt](https://platform9.com/kb/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://platform9.com/kb/pmk/frequently-asked-questions/the-certificate-being-used-by-the-k8s-api-server-on-port-443-is.md).

# The certificate being used by the k8s API server on port 443 is an untrusted certificate.

## Problem

* Vulnerability checks report that the certificate used by the k8s API server on port 443 is not a trusted certificate.
* Why not use a certificate signed by a trusted third-party Certificate Authority in PMK?

## Environment

* Platform9 Managed Kubernetes - All Versions
* Pf9-Vault

## Answer

* PMK uses [HashiCorp Vault](https://www.hashicorp.com/products/vault) to manage certificates. The certificates are issued by Vault's internal CA and are trusted within the environment. However, they may be flagged as untrusted by external tools unless the CA certificate is added to their trust stores.
* Third-party CAs are useful when there are a large number of clients and they are unaware of the CA used by the server.
* It is standard practice to use self-signed certificates to connect to the API server. From a Kubernetes perspective, the clients are known - they are the worker nodes and clients connecting using a kubeconfig.
* In both cases, they are preconfigured to use the CAs generated by PMK. [Platform9](https://platform9.com/) owns the complete workflow of creating these certificates, distributing them to the server and clients, and rotating them when they are about to expire.
* So, In this scenario, there won't be any additional security benefits of using third-party CAs.

## Additional Information

If the customer is using [Qualys](https://www.qualys.com/apps/web-app-scanning/) for vulnerability checks:

* The Qualys scan will report the certificates used by the API server as untrusted, which means the certificates issued by Vault are self-signed by Vault's internal CA, and the Qualys scanner does not have Vault's CA certificate in its trust store.
* Qualys has a way to pass in custom CAs that it can trust during its tests: [**https://qualysguard.qualys.eu/qwebhelp/fo\_portal/setup/win\_trusted\_ca.htm**](https://qualysguard.qualys.eu/qwebhelp/fo_portal/setup/win_trusted_ca.htm)**.**


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://platform9.com/kb/pmk/frequently-asked-questions/the-certificate-being-used-by-the-k8s-api-server-on-port-443-is.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `build a script that syncs our docs to a CMS` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.