Device resolver

The device resolver identifies devices when the devices connect to the network.

The device resolver on the SafeLinx Server works with network access servers (NAS) to uniquely identify devices whenever the devices connect to the network. The unique identity of a device is required before the SafeLinx Server passes the device identity in requests to other web servers and proxies in the network. When you enable the device resolver, this unique identifier is passed from the NAS upon request to the SafeLinx Server in the form of RADIUS authentication or RADIUS accounting messages.

The type of RADIUS messages that are sent from the NAS (authentication or accounting) depends on the NAS configuration and whether any other authentication or accounting servers exist in the network. You can configure the device resolver to return RADIUS responses directly back to the NAS, or you can configure it as a proxy. As a proxy, the device resolver forwards RADIUS messages to other servers in the network, then returns the subsequent responses to the NAS.

Because the NAS is configured to distribute an IP address from a pool of addresses to users as they connect to the network, this IP address does not uniquely identify a specific user. Because clients do not typically use the same address each time they connect to the network, the NAS must be configured to also send another identifier that uniquely identifies the device.

The unique identifier that is sent by the NAS is defined in the device resolver in terms of its RADIUS attribute type. These attribute types are defined in RADIUS authentication RFC 2865 and RADIUS accounting RFC 2866.

Configuring the device resolver consists of two parts:
  • Adding a device resolver to the SafeLinx Server
  • Enabling the device resolver

When you add a device resolver, you define information about the NAS, the ports on which the SafeLinx Server will listen for incoming RADIUS messages from the NAS, the type of unique device identifier, and optional RADIUS proxy forwarding options. You must add a device resolver for each network access server to which devices will connect. To add a device resolver resource, right-click the SafeLinx Server to which you want to add it, then click Add > Device resolver.

Note: Users who are identified by the device resolver are not displayed as active users in the SafeLinx Administrator.