Network access session detection to provide single-sign on (SSO) functionality for a network access control device

A method comprising:

• receiving, with a network access control (NAC) device, a security assertion request from a user agent executing on a client device, the security assertion request including a request for a security assertion to be made by the NAC device, the security assertion indicating that a user of the user agent has been authenticated by the NAC device;
• sending, with the NAC device, a redirect message to the user agent in response to receiving the security assertion request, the redirect message including information indicative of the security assertion request;
• and
• selectively issuing, with the NAC device, a security assertion that is responsive to the security assertion request without requiring the user to re-authenticate with the NAC device based on whether the NAC device receives session verification information from a NAC client executing on the client device in response to sending the redirect message to the user agent.