How can we use separate flies for logging authentication and accouting information.

raddb/modules/detail.log

Also wanted to know does free radius configure the access list on the interface, similar to the ip address.

Sort of. You configure a list of clients from which requests will be accepted.

One more quick question, how can we set timeout for different users, so if the connection is ideal for say 4 hrs, it should get disconnected.

See Session-Timeout attribute. Ivan Kalik Kalik Informatika ISP