[Help-gnu-radius] Restricting router/radius access question

[Gerald]

When a workstation tries to authenticate to a router which is pointed to a
radius server for authentication. What part of the Auth request shows the
workstation's IP?

Client --> Router --> Radius server

I want to make an entry in the attrib DB to limit auth in this scenario to
certain Clients (workstations). NAS-IP-Address would be the IP of the
router. Would the client's IP be sent in the Auth request packet? Could I
setup Framed-IP = x.x.x.x to limit authentication for that user to that
IP?

Thanks for help in advance.

Gerald