Seeking Agentless SSO Solutions for Non-Web Service Access within a Private Network

Hello Community,

We manage a private network composed of our own data centers and public cloud services like AWS and GCP. Currently, PCs in our office locations access this network via Site-to-Site VPN. We are looking to enable these PCs to authenticate through our custom SSO service without needing any additional client software.

We’re aware that Cloudflare offers an agentless solution for accessing web services via a browser. However, we need a solution for non-web service access. Specifically, we want to access GitLab servers hosted on our private network using SSO, without installing any agents on the PCs at our office locations.

Does anyone have experience with or know of any solutions that support agentless and SSO-authenticated access to non-web services like GitLab? Any recommendations would be highly appreciated.

Thank you!