Welcome, @chripede.
Thanks for reaching out. The security team has confirmed that we do not support or plan to support using proxy servers to access HubSpot CDN-hosted content.
This includes using X-Forwarded-For headers. As David states in the other topic, your users may not experience issues with this immediately, but we cannot guarantee reliability under any circumstances.
That said, you can maintain your current URL structure (with different content hosted on different subdirectories) just as long as it’s on a HubSpot-hosted subdomain (e.g. www.domain/blog instead of just domain/blog). Said differently, you don’t have to host your blog on blog.domain.com and your knowledge base on knowledge.domain.com just because you are moving onto HubSpot. If you’d like to discuss these options in more detail, feel free to reach out to HubSpot support.