Wi-Fi, also known as 802.11b (the name assigned to the standard by the Institute of Electrical and Electronic Engineers), is by far the most common tool for wireless computer access to the Internet and home and office networks. Now researchers in Australia are warning against relying on Wi-Fi for “mission-critical” communications. As MacCentral reported yesterday, the researchers have discovered a flaw in the 802.11b standard that could allow anyone with a $35 wireless adaptor to interfere with Wi-Fi signals over a one-kilometer radius, effectively shutting down the networks within range. “Any organization that continues to use the standard wireless technology (IEEE 802.11b) to operate critical infrastructure could be considered negligent,” said Mark Looi, an associate professor in Queensland University of Technology’s School of Software Engineering. Looi and colleagues are presenting their results today at the IEEE Wireless Telecommunication Symposium in Pomona, California.