Wireless Ethernet Bridge

A wireless Ethernet bridge converts a wired Ethernet device for use on a wireless computer network. Wireless Ethernet bridges and USB adapters are both sometimes called wireless media adapters as they enable devices for WiFi utilizing Ethernet or USB physical media. Wireless Ethernet bridges support game consoles, digital video recorders and other Ethernet-based consumer devices as well as ordinary computers.

The Linksys WET54G Wireless Ethernet Bridge (compare prices) is shown above. It is only a bit larger than Linksys' wireless USB adapter.

True network bridge devices like the WET54G do not require device driver software installation in order to function, simplifying installation. Instead, network settings for the WET54G can be made through a browser-based administrative interface.

Like USB adapters, wireless Ethernet bridges can draw their power from the main cable connected to the host device. Ethernet bridges require a specialized Power over Ethernet (PoE) converter to make this work, however, whereas this functionality is automatic with USB. Without a PoE add-on, wireless Ethernet bridges need a separate power cord.

Wirelss Ethernet bridges commonly feature LED lights. The WET54G, for example, displays lights for power, Ethernet and Wi-Fi status.

Wireless CompactFlash Card Adapter for PDAs

Wireless CompactFlash (CF) cards like the Linksys WCF54G (compare prices) shown above are designed for use in Pocket PC devices running the Microsoft Windows CE operating system. These adapters enable PDA devices for standard Wi-Fi networking.

Like PC Card adapters for notebook computers, wireless CompactFlash cards fit into a slot on the side or back of a PDA. The portion of the device containing the Wi-Fi antenna and LED lights protrudes from the PDA.

CompactFlash card network adapters obtain their power from the PDA batteries and are designed to minimize the unit's power consumption.

Wireless USB Network Adapter

The Linksys WUSB54G (compare prices) shown above is a typical WiFi wireless USB network adapter. These adapters connect to a standard USB port available on the back of most newer computers. In general, USB network adapters are not much larger in size than PC Card adapters. Two LED lights on the adapter indicate its power and network link status.

Installation of a wireless USB adapter is simple. A short USB cable (normally included with the unit) joins the adapter to the computer. These adapters do not require a separate power cord, as the same USB cable also draws power from the host computer. The USB adapter's wireless antenna and circuitry remain external to the computer at all times. On some units, the antenna can be adjusted manually to improve WiFi reception. The accompanying device driver software serves an equivalent function as in other types of network adapters.

Some manufacturers market two kinds of wireless USB adapters, a "basic" model and a "compact" model designed for travelers. Their small size and easy setup make these adapters an attractive choice for those who want to simplify their network setup.

Wireless PC Card Adapter for Notebook Computers

A PC Card adapter joins a notebook computer to the network. The PC Card is a device approximately the width and height of a credit card compatible with the PCMCIA hardware interface standard.

The Linksys WPC54G (compare prices) shown above is a typical PC Card network adapter for notebook computers. This adapter contains a very small built-in Wi-Fi antenna to provide wireless capability. It also features built-in LED lights that display the device status.

PC Card devices insert into a slot on the side of a notebook computer. Wireless adapters like the one shown typically protude a small amount from the side of the computer; this allows Wi-Fi antennas to transmit without interference. In contrast, wired Ethernet PC Card adapters insert fully inside the computer.

Given the small space they fit into, PC Card adapters become very warm during normal operation. This is not a major concern as the adapters are designed to withstand heat. However, notebook computers provide an eject mechanism to remove PC Card adapters when not in use to protect them and possibly extend their life.

PCI Wireless Adapter Card for Desktop Computers

PCI stands for "Peripheral Component Interconnect," an industry standard for connecting devices to a computer's central processor. PCI works by establishing a common interconnect called a bus that all connected devices share for communication. PCI is the most common interconnect used in desktop personal computers.

A PCI wireless adapter card connects to a desktop computer's PCI bus. Because the PCI bus is contained inside the computer, the unit must be opened and the wireless network adapter installed inside.

An example of a PCI wireless adapter card, the Linksys WMP54G (compare prices) is shown above. This unit is more than 8 inches (200 mm) long in order to accommodate the standard connection strip required to electrically join to the bus. The unit attaches and fits snugly inside the PCI, although the wireless adapter card antenna protrudes out the back of the computer.

broadband router

Definition: A broadband router combines the features of a traditional network switch, a firewall, and a DHCP server. Broadband routers are designed for convenience in setting up home networks, particularly for homes with high-speed cable modem or DSL Internet service. A broadband router supports file sharing, Internet connection sharing, and home LAN gaming.

A broadband router follow the Ethernet standard for home networking. Traditional broadband routers required Ethernet cables be run between the router, the broadband modem, and each computer on the home LAN. The newer wireless routers also support broadband Internet access and the Ethernet standard without the need for cabling.

Several manufacturers offer broadband router products to the consumer. Features that differentiate broadband router products include the number and type of ports available on the unit for cabling computers, external modems, or other network devices.

NAT - Network Address Translation

Definition: NAT allows an Internet Protocol (IP) network to maintain public IP addresses separately from private IP addresses. NAT is a popular technology for Internet connection sharing. It is also sometimes used in server load balancing applications on corporate networks.

In it's most common configuration, NAT maps all of the private IP addresses on a home network to the single IP address supplied by an Internet Service Provider (ISP). This allows computers on the home LAN to share a single Internet connection. Additionally, it enhances home network security by limiting the access of external computers into the home IP network space.

NAT works by snooping both incoming and outgoing IP datagrams. As needed, it modifies the source or destination address in the IP header (and the affected checksums) to reflect the configured address mapping. NAT technically supports either fixed or dynamic mappings of one or more internal and external IP addresses.

NAT functionality is usually found on routers and other gateway devices at the network boundary. NAT can also be implemented entirely in software. Microsoft's Internet Connection Sharing (ICS), for example, adds NAT support to the Windows operating system.

By itself, NAT does not provide all the features of a true firewall, but it is often used on servers that feature other firewall and antivirus support. NAT was designed originally to conserve public Internet address space. Internet RFC 1631 contains the basic NAT specification.

Can You Hide Your Public IP Address?

When connecting to the Internet, your home computer (or network router) is assigned a public IP address. As you visit Web sites or other Internet servers, that public IP address is transmitted and recorded in log files kept on those servers. Access logs leave behind a trail of your Internet activity. If it were possible to somehow hide your public IP address, your Internet activity would become much more difficult to trace.

Answer: Unfortunately, it is not technically possible to always hide the public IP address of a home network. An IP address enables devices to locate and communicate with each other on the Internet. Completely hiding the IP address of a device would render it invisible but also unusable online.

On the other hand, it is possible to hide public IP addreseses from most Internet servers in most situations. This method involves an Internet service called an anonymous proxy server.

Anonymous Proxy Servers

An anonymous proxy server ("proxy") is a special type of server that acts as an intermediary between a home network and the rest of the Internet. An anonymous proxy server makes requests for Internet information on your behalf, using its own IP address instead of yours. Your computer only accesses Web sites indirectly, through the proxy server. This way, Web sites will see the proxy's IP address, not your home IP address.

Using an anonymous proxy server requires a simple configuration of the Web browser (or other Internet client software that supports proxies). Proxies are identified by a combination of URL and TCP port number.

Numerous free anonymous proxy servers exist on the Internet, open for anyone to use. These servers may have bandwidth traffic limits, may suffer from reliability or speed problems, or might permanently disappear from the Internet without notice. Such servers are most useful for temporary or experimental purposes.

Anonymous proxy services that charge fees in return for better quality of service also exist. These services are designed for regular use by households.

Hiding Your IP Address - Related Tools

Several related software tools (both free and paid versions) support anonymizing proxies. The Firefox extension called "switchproxy," for example, supports defining a pool of proxy servers in the Web browser and automatically switching between them at regular time intervals. In general, these tools help you both find proxies and also simplify the process of configuring and using them.

The ability to hide an IP address increases your privacy on the Internet. Other approaches to improving Internet privacy also exist and complement each other. Managing Web browser cookies, using encryption when sending personal information, running a firewall and other techniques all contribute toward a greater feeling of safety and security when going online.

Firewall

Definition: A network firewall protects a computer network from unauthorized access. Network firewalls may be hardware devices, software programs, or a combination of the two.

Network firewalls guard an internal computer network (home, school, business intranet) against malicious access from the outside. Network firewalls may also be configured to limit access to the outside from internal users.

Network Firewalls and Broadband Routers

Many home network router products include built-in firewall support. The administrative interface of these routers include configuration options for the firewall. Router firewalls can be turned off (disabled), or they can be set to filter certain types of network traffic through so-called firewall rules.

Network Firewalls and Proxy Servers

Another common form of network firewall is a proxy server. Proxy servers act as an intermediary between internal computers and external networks by receiving and selectively blocking data packets at the network boundary. These network firewalls also provide an extra measure of safety by hiding internal LAN addresses from the outside Internet. In a proxy server firewall environment, network requests from multiple clients appear to the outsider as all coming from the same proxy server address.

ISP - Internet Service Providers

Definition: An ISP is a company that supplies Internet connectivity to home and business customers. ISPs support one or more forms of Internet access, ranging from traditional modem dial-up to DSL and cable modem broadband service to dedicated T1/T3 lines.

More recently, wireless Internet service providers or WISPs have emerged that offer Internet access through wireless LAN or wireless broadband networks.

In addition to basic connectivity, many ISPs also offer related Internet services like email, Web hosting and access to software tools.

A few companies also offer free ISP service to those who need occasional Internet connectivity. These free offerings feature limited connect time and are often bundled with some other product or service.