Networking Solution Many Different Technologies

Networking Solution

Many different technologies are suitable for networking home computers, and the same problems can be solved effectively many different ways. In this case, the goal is to provide a reasonably secure home network consisting of a desktop PC, three laptop computers and two printers with the ability to share an Internet connection between all of the computers, share files, access the printers and access the desktop PC remotely. Being connected to the public Internet, this network must employ security precautions to prevent unauthorized access by arbitrary remote users. Since detailed descriptions of the equipment in question were not provided, it is necessary to make some assumptions about the hardware and software environment. The desktop PC will be a home-built unit using high-quality components. The laptops will be recent-model IBM Thinkpads and the Internet connection will be a cable modem with an Ethernet connection. For simplicity, all the computers will run the same operating system: Ubuntu Linux 6.06.

The cable modem will be connected directly to the Ethernet port of the desktop PC. The PC will be configured to obtain an Internet Protocol (IP) address from the Internet Service Provider (ISP) using the Dynamic Host Configuration Protocol (DHCP). The desktop PC will have an 802.11g wireless card installed and configured to act as a wireless access point. The wireless network will use WiFi Protected Access (WPA) to prevent unauthorized users from connecting to the network or intercepting communications. The laptop computers will all be configured to use static IP addresses, and will all have identical hosts files mapping easily remembered names to those addresses. The desktop computer will also allow users of the wireless network who have been authenticated using WPA to request assignment of an IP address using DHCP. Unauthorized users will be prevented from connecting to the network by WPA, therefore it is not necessary to control access to DHCP. Access to the DHCP port from the public Internet will be blocked by the firewall's configuration. To provide a firewall controlling remote access to the network services, the desktop computer will run netfilter, configured using the graphical Firestarter front end.

All the computers will offer Secure Shell (SSH) services using OpenSSH server. SSH provides secure remote control and file access even over an unsecured network. Ubuntu's default Gnome desktop environment provides the ability to access remote files over SSH using the same graphical file browser used for local files. FreeNX will be installed on the desktop computer for remote access to graphical applications. Clients for the NX protocol exist for all major computing platforms, allowing for good performance from desktop applications over any broadband connection. The firewall may be configured to restrict SSH access to specific remote IP addresses to prevent arbitrary users from attempting to gain access.