Default Proxy for checking payload.

Hi folks,

How does default-proxy setting work when there is no explicit web proxy enabled or configured? Is it impersonating all user sessions and creating another tcp session for outbound traffic or it just predent, that is is enabled but non functional? 

I was looking for a way, how to check payload of secure traffic - for example HTTPS traffic. SSL deep inspection is not a solution due not owning a whole CA certificate. I found a way, that this might be done through SSL Offloading via Virtual server (at least I hope that it works).

Can someone brief me into this? 

Thanks !