IP Address 192.168.0.5 Subnet Mask .255.255.255.255 Default Gateway 192.168.0.7 in Visual Basic .NET

Drawing PDF 417 in Visual Basic .NET IP Address 192.168.0.5 Subnet Mask .255.255.255.255 Default Gateway 192.168.0.7

To resolve network connectivity problems, you should test network cabling con nections, the network adapter in a computer, the network configuration on a com puter, and verify that any required servers are online. You can configure local area and dial-up network connections using the Network Connections window in Windows XP. Use a particular connection s Properties dia log 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 configu ration 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 automat ically by using APIPA. You can also configure the TCP/IP information for a com puter 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.

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A firewall protects a computer from external network traffic (specifically, the Internet) by blocking all network traffic except that which you specifically configure the firewall to allow through. This section introduces firewalls and looks at the host-based firewall that is included with Windows XP with Service Pack 2: Windows Firewall.

Explain how firewalls protect computers. Enable or disable Windows Firewall for all network connections. Enable or disable Windows Firewall for a specific network connection. Configure advanced options for Windows Firewall. Troubleshoot connectivity problems that are associated with Windows Firewall.

A firewall acts as a security system that creates a border between the computer or network and the Internet. This border determines what traffic is allowed in the local network or computer. Firewalls help keep hackers, viruses, and other malicious activity from infiltrating the computer and network. A perimeter-based firewall is a device that protects an entire network. A host-based firewall is a program that protects a single computer. Windows XP includes a host-based firewall named Windows Firewall. Windows Firewall is installed when you install Windows XP Service Pack 2, and is an updated version of the Internet Connection Firewall (ICF) found on versions of Windows XP with Service Pack 1 and previous. Windows Firewall is a stateful, hostbased firewall that drops all incoming traffic that does not meet one of the following conditions:

Solicited traffic (valid traffic that is received in response to a request by the com puter) is allowed through the firewall. Expected traffic (valid traffic that you have specifically configured the firewall to accept) is allowed through the firewall.

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Windows Firewall has the following characteristics:

Is enabled by default for all network connections. This differs from Internet Con nection Firewall, which was not enabled by default. Limits the network traffic that comes into a computer by blocking transmission over all ports except those specifically configured to allow traffic to reach the computer. When you allow a specific type of traffic into a computer through Windows Firewall, this is called creating an exception. You can create exceptions by specifying the file name of an application or by configuring specified ports for which to allow traffic. Windows Firewall lets you create separate exceptions for each network connection. This differs from Internet Connection Firewall, which only allowed you to create global exceptions that affected all connections. Can restrict traffic by IP address (or IP address range), meaning that only traffic from computers with valid IP addresses is allowed through the firewall. Allows you to enable or disable Windows Firewall on each connection configured on a computer running Windows XP, whether that connection is a LAN connec tion, dial-up connection, or wireless connection. You can also set global config urations that affect all connections. This differs from Internet Connection Firewall, which only allowed you to enable or disable the firewall globally for all connections. Allows you to keep a security log of blocked traffic so that you can view firewall activity. Performs stateful packet filtering during startup, so that the computer can perform basic network tasks (such as contacting DHCP and DNS servers) and still be pro tected. This differs from Internet Connection Firewall, which did not perform any filtering during startup.