Question Turn a laptop with VPN on it into a proxy ?

Feb 7, 2022
Machine A: is a laptop running Windows 10 Enterprise and a locked down version of Pulse Secure VPN client - all it can do is connect/disconnect.
Machine B: is a desktop running Ubuntu 22.04

They are both connected to the same local broadband router. I do have admin access for both machines and the router. I also have a remote linux server C that could serve as an intermediate node if needed.

Is it possible to turn A into a proxy so that B could use it while the VPN on A is connected?

It's not possible to get the VPN credentials to use directly on B, otherwise I wouldn't be asking this question.
Not very likely.
Corporate vpn most times is designed to prevent exactly what you are talking about. They do not want any data or machines on the corporate network that are not authorized. Many block even simple access to local lan file shares and even printer on the local network. This prevents getting virus and other software onto the corporate network. If they allowed you connect other machines the corporate network security now is only as good as your skills. What happens if you were really stupid and connected a router that allowed open access to get one the corporate network.

The only way to make this work is to manipulate the routing table in the local machine. In most cases these corporate vpn detect any attempt to change the routing and terminate the vpn session.

It would be very messy to do even if you had full control over the vpn client.