IT Infrastructure 1. User Domain 2. Workstation Domain 3. LAN Domain 4. LAN-to-WAN Domain 5. WAN Domain 6. Remote Access Domain 7. System/Application Domain Each of the areas of the IT infrastructure areas represents different segments in both logical and physical representation. Security controls can be placed into the environment at many of the same areas at the same time. If mitigation techniques are used in several of the domains, then you can achieve an increasing level of defense-in-depth.