Perimeter Networks

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An Internet-facing host accepts or initiates connections from or to hosts on the public Internet.

• placed in the perimeter network zone
  • basic principle
    • traffic cannot pass through it directly
    • enables external clients to access data on private systems without compromising security
• communications between internal and external networks should pass through a proxy in the perimeter network
  • e.g.,
    • host on local network requests a connection with a web server on the Internet
      • proxy takes the request and checks it
      • if valid, transmits it
      • to external host, all comms seem initiated by the proxy
      • external host has not direct connectivity to the LAN device
• servers that provide public access services should be placed in perimeter network
  • e.g., web servers, mail servers, proxy servers, remote access servers
• hosts in perimeter network are not fully trusted by internal network