A network system server, at a first network site, maintains network access information that identifies users authorized to access a network and a network controller, at a second network site, caches the network access information for individual users that request access to the network from the second network site. The network controller tracks the individual users that request access to the network from the second network site and updates the cached network access information for the individual users that request access to the network from the second network site within a defined time interval.