Wi-Fi refers to wireless local area network technology that uses the 802.11 standards. It was developed by the IEEE and branded as "Wi-Fi" by the Wi-Fi Alliance trade group to promote interoperability between wireless devices. Wi-Fi allows devices like computers, phones, and other electronics to connect to the internet or communicate with each other wirelessly within a particular range using radio waves. While convenient, Wi-Fi connections pose security risks if not encrypted, though newer standards like WPA2 aim to address this when configured correctly.

1. BY : S. GURUPRASAD

2. Wi-Fi refers to any system that uses the 802.11 standard, which was developed by the Institute of Electrical and Electronics Engineers (IEEE). The term Wi-Fi , which is alternatively spelled WiFi, Wi-fi, Wifi, or wifi, was pushed by the Wi-Fi Alliance, a trade group that pioneered commercialization of the technology. Wi-Fi is a trademark of the Wi-Fi Alliance for certified products based on the IEEE 802.11 standards. This certification warrants interoperability (inter-operate) between different wireless devices. WHAT'S WI-FI ??

3. Not every IEEE 802.11 compliant device is certified by the Wi-Fi Alliance, which may be because of certification costs that must be paid for each certified device type. The lack of the Wi-Fi logo does not imply that a device is incompatible to certified Wi-Fi devices. Wi-Fi is used by most personal computer operating systems, many video game consoles, laptops, smart phones, printers, and other peripherals. There are 4 types of IEEE 802.11 standards: 1. 802.11a 2. 802.11b 3. 802.11g 4. 802.11n

4. A Wi-Fi enabled device such as a PC, video game console, mobile phone, MP3 player or PDA can connect to the Internet when within range of a wireless network connected to the Internet. The coverage of one or more interconnected access points — called a hotspot — can comprise an area as small as a single room with wireless-opaque walls or as large as many square miles covered by overlapping access points. In addition to restricted use in homes and offices, Wi-Fi can make access publicly available at Wi-Fi hotspots provided either free of charge or to subscribers to various providers. Organizations and businesses such as airports, hotels and restaurants often provide free hotspots to attract or assist clients. Enthusiasts or authorities who wish to provide services or even to promote business in a given area sometimes provide free Wi-Fi access. USES OF WI-FI

5. There are already more than 300 metropolitan-wide Wi-Fi (Muni-Fi) projects in progress. Wi-Fi also allows connectivity in peer-to-peer (wireless ad hoc network) mode, which enables devices to connect directly with each other. This connectivity mode can prove useful in consumer electronics and gaming applications. When wireless networking technology first entered the market many problems ensued for consumers who could not rely on products from different vendors working together. The Wi-Fi Alliance began as a community to solve this issue — aiming to address the needs of the end-user and to allow the technology to mature. The Alliance created the branding Wi-Fi CERTIFIED to reassure consumers that products will interoperate with other products displaying the same branding.

6. Allows LANs to be deployed without cabling, typically reducing the costs of network deployment and expansion. Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs. Wi-Fi silicon pricing continues to come down, making Wi-Fi a very economical networking option and driving inclusion of Wi-Fi in an ever-widening array of devices. Wi-Fi products are widely available in the market. Different brands of access points and client network interfaces are interoperable at a basic level of service. Products designated as Wi-Fi CERTIFIED by the Wi-Fi Alliance are interoperable and include WPA2 security. Wi-Fi networks support roaming, in which a mobile client station such as a laptop computer can move from one access point to another as the user moves around a building or area. ADVANTAGES

7. Wi-Fi is a global set of standards. Unlike cellular carriers, the same Wi-Fi client works in different countries around the world. Widely available in more than 250,000 public hot spots and millions of homes and corporate and university campuses worldwide. As of 2006, WPA and WPA2 encryption are not easily crackable if strong passwords are used New protocols for Quality of Service (WMM) and power saving mechanisms (WMM Power Save) make Wi-Fi even more suitable for latency-sensitive applications (such as voice and video) and small form-factor devices.

8. Reach Wi-Fi performance decreases roughly quadratically as distance increases at constant radiation levels. Due to reach requirements for wireless LAN applications, power consumption is fairly high compared to some other standards. Technologies such as Bluetooth, which are designed to support wireless PAN applications, provide a much shorter propagation range of <10m and so in general have lower power consumption. The high power consumption of Wi-Fi makes battery life a concern for mobile devices. Mobility Because of the very limited practical range of Wi-Fi, mobile use is essentially confined to such applications as inventory taking machines in warehouses or retail spaces, barcode reading devices at check-out stands or receiving / shipping stations. DISADVANTAGES

9. Threats to security The most common wireless encryption standard, Wired Equivalent Privacy or WEP, has been shown to be easily breakable even when correctly configured. Wi-Fi Protected Access (WPA and WPA2), which began shipping in 2003, aims to solve this problem and is now available on most products. Wi-Fi Access Points typically default to an &quot;open&quot; (encryption-free) mode. Wi-Fi networks that are open (unencrypted) can be monitored and used to read and copy data (including personal information) transmitted over the network, unless another security method is used to secure the data, such as a VPN or a secure web page (HTTPS/Secure Socket Layer). Population Many 2.4 GHz 802.11b and 802.11g access points default to the same channel on initial startup, contributing to congestion on certain channels. To change the channel of operation for an access point requires the user to configure the device. Network security The main issue with wireless network security is its simplified access to the network compared to traditional wired networks such as Ethernet. With wired networking it is necessary to either gain access to a building, physically connecting into the internal network, or break through an external firewall. Most business networks protect sensitive data and systems by attempting to disallow external access. Thus being able to get wireless reception provides an attack vector, if encryption is not used or can be defeated. Attackers who have gained access to a Wi-Fi network can attack very effectively against any other user of the network, because they can see the DNS requests made, and often respond with a spoofed answer before the queried DNS server has a chance to reply.

10. Securing methods 1. SSID  A common but unproductive measure to deter unauthorized users is to suppress the AP's SSID broadcast, &quot;hiding&quot; it. This is ineffective as a security method because the SSID is broadcast in the clear in response to a client SSID query. 2. MAC Address  Another unproductive method is to only allow computers with known MAC addresses to join the network. The fault with this method is MAC addresses can often, but not always, be set by a user (spoofed) with minimal effort. If the eavesdropper has the ability to change his MAC address, then he may join the network by spoofing an authorized address. 3. WEP  Wired Equivalent Privacy (WEP) encryption was designed to protect against casual snooping, but is now considered completely broken. Tools such as Air Snort or Aircrack-ng can quickly recover WEP encryption keys. Once it has seen 5-10 million encrypted packets, Air Snort can determine the encryption password in under a second; newer tools such as Aircrack-ptw can use Klein's attack to crack a WEP key with a 50% success rate using only 40,000 packets. SECURING A WI FI CONNECTION

11. 4. WPA  The Wi-Fi Alliance blessed Wi-Fi Protected Access (WPA) which uses TKIP as a stopgap solution for legacy equipment. Though more secure than WEP, it has outlived its designed lifetime, has known attack vectors and is no longer recommended. 5. WPA2  The full IEEE 802.11i (WPA2) encryption standards were released. If used with a 802.1X server or in pre-shared key mode with a strong and uncommon pass phrase WPA2 is still considered secure, as of 2009.