Chapter Summary

• Each interface on a TCP/IP network is assigned a unique IP address, which is typically shown as four decimal numbers ranging from 0 to 255. An IP address is divided into a network ID, which determines the subnet on which a host exists, and a host ID, which uniquely identifies the host on that subnet. The separation of network ID and host ID is determined by a subnet mask.

• A default gateway is the IP address to which a client sends data that is destined for a host that is not on the same network as a client. The default gateway is typically a router.

• Name resolution is the process of mapping IP addresses to computer or host names. DNS is the primary name resolution mechanism used on modern Windows networks and on the Internet. WINS is a name resolution mechanism used on older Windows-based networks.

• To resolve network-connectivity problems, you should test network cabling connections, the network adapter in a computer, the network configuration on a computer, and verify that any required servers are online.

• You can configure local area and dial-up network connections by using the Network Connections window in Windows XP. Use a particular connection’s Properties dialog box to configure the connection settings.

• Windows XP computers can obtain an IP address automatically by searching the network for a DHCP server. If found, the DHCP server provides TCP/IP configuration information to the client. If the computer cannot contact a DHCP server, Windows XP assigns the computer an IP address in the 169.254.0.0 range automatically by using APIPA. You can also configure the TCP/IP information for a computer manually.

• Use the Ping, Tracert, and Pathping commands to test TCP/IP connectivity.

• Use the Ipconfig /all command to show detailed information about the TCP/IP configuration of a computer—including the IP address, subnet mask, default gateway, DNS servers, and DHCP information about every network connection on a system.

• Internet Connection Firewall is a software-based firewall built in to Windows XP. You can enable ICF for any network connection, and configure what types of traffic it allows to enter or leave the computer.

• Internet Control Message Protocol allows routers and host computers to swap basic control information when data is sent from one computer to another. ICMP tools such as Ping and Tracert are often used to troubleshoot network connectivity.

• Most of the problems you will encounter with ICF include users not being able to enable ICF for a particular connection, and users having connectivity problems resulting from having ICF turned on and blocking necessary traffic.

• Remote Assistance enables users to request support from a more advanced user or from computer support personnel. With Remote Assistance, the user providing support can connect to the troubled user’s desktop, view what is happening remotely, and take control of the system to resolve a problem if necessary.

• Remote Desktop enables users to remotely access their computers across the network and use the desktop as if they were sitting in front of the computer.