I have a multi-user machine with several network interfaces (Ethernet, if that matters). I wish to grant selected users, or groups, full access to selected network interfaces (including ability to adjust IP address and to bind to low ports, but *only* on those interfaces). It is important to me that an user/group does not such full control over other interfaces. Granting partial, or temporary, root permissions is OK; it's a friendly environment.
How do I go about it?
System: Linux 2.6.recent; usual Debian setup (can be adjusted if needed).
Thank you in advance