IEEE 802.11 is part of the IEEE 802 set of LAN protocols, and specifies the set of media access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) Wi-Fi computer communication in various frequencies, including but not limited to 2.4 GHz, 5 GHz, and 60 GHz frequency bands.
802.11-1997 2.4 GHz 1 Mbit/s or 2 Mbit/s (LEGACY)
802.11b 2.4 GHz 11 Mbit/s (WiFi 1)
802.11a 5GHz 54 Mbit/s (WiFi 2)
802.11g 2.4 Ghz 54 Mbit/s (WiFi 3)
802.11n 2.4 and 5 GHz, up to 600 Mbit/s (WiFi 4)
802.11ac 5GHz up to 1300 Mbit/s, Wave 2 up to 3,5 Gbit/s (WiFi 5)
802.11ad (WiGig) 60 GHz, 8 Gbit/s
802.11ax 2.4+5 GHz (1-6 GHz) up to 14 Gbit/s (WiFi 6)
channels on 2.4 GHz band
channel interference and open channel
adjacent vs. co-channel congestion
channels on 5 GHz band, 20-160 MHz wide channels
channel numbers vs. channel width
Dynamic Frequency Selection (DFS) is a channel allocation schemes specified for wireless LAN, commonly Wi-Fi. It is designed to prevent electromagnetic interference with other usages of the C band frequency band that had predated Wi-Fi, such as military radar, satellite communication, and weather radar.
Transmit power control (TPC) is a technical mechanism used within some networking devices in order to prevent too much unwanted interference between different wireless networks (e.g. the owner's network and the neighbour's network).
|-30 dBm||Amazing||Max achievable signal strength. The client can only be a few feet from the AP to achieve this. Not typical or desirable in the real world.|
|-67 dBm||Very Good||Minimum signal strength for applications that require very reliable, timely delivery of data packets.|
|-70 dBm||Okay||Minimum signal strength for reliable packet delivery.|
|-80 dBm||Not Good||Minimum signal strength for basic connectivity. Packet delivery may be unreliable.|
|-90 dBm||Unusable||Approaching or drowning in the noise floor. Any functionality is highly unlikely.|
Several household electronics can be sabotaging your Wi-Fi performance:
To build a key from shared secret, the key derivation function is typically used. Such systems almost always use symmetric key cryptographic algorithms. The term PSK is used in Wi-Fi encryption such as Wired Equivalent Privacy (WEP), Wi-Fi Protected Access (WPA), where the method is called WPA-PSK or WPA2-PSK.
In all these cases, both the wireless access points (AP) and all clients share the same key.
WPA2 (IEEE 802.11i)
The standard also provides two RSNA data confidentiality and integrity protocols, TKIP and CCMP, with implementation of CCMP being mandatory since the confidentiality and integrity mechanisms of TKIP are not as robust as those of CCMP. The main purpose to implement TKIP was that the algorithm should be implementable within the capabilities of most of the old devices supporting only WEP.
The initial authentication process is carried out either using a pre-shared key (PSK), or following an EAP exchange through 802.1X (WPA-Enterprise), which requires the presence of an authentication server.
But TKIP still can be enabled by default...
But TKIP still can be enabled by default...
New, improved version of EAP is called Extended EAP and is available in several versions; these include: EAP-MD5, PEAPv0, PEAPv1, EAP-MSCHAPv2, LEAP, EAP-FAST, EAP-TLS, EAP-TTLS, MSCHAPv2, and EAP-SIM
The Protected Extensible Authentication Protocol, also known as Protected EAP or simply PEAP, is a protocol that encapsulates the Extensible Authentication Protocol (EAP) within an encrypted and authenticated Transport Layer Security (TLS) tunnel. The purpose was to correct deficiencies in EAP.
First EAP assumed a protected communication channel, such as that provided by physical security, so facilities for protection of the EAP conversation were not provided.
The IEEE 802.11 (Wi-Fi) protocol contains the provision for a deauthentication frame. Sending the frame from the access point to a station is called a "sanctioned technique to inform a rogue station that they have been disconnected from the network".
An attacker can send a deauthentication frame at any time to a wireless access point, with a spoofed address for the victim. The protocol does not require any encryption for this frame, even when the session was established with Wired Equivalent Privacy (WEP) for data privacy, and the attacker only needs to know the victim's MAC address, which is available in the clear through wireless network sniffing.
One of the main purposes of deauthentication used in the hacking community is to force clients to connect to an Evil twin access point which then can be used to capture network packets transferred between the client and the AP.
The attacker conducts a deauthentication attack to the target client, disconnecting it from its current network, thus allowing the client to automatically connect to the Evil twin access point.
In order to mount a brute-force or dictionary based WPA password cracking attack on a WiFi user with WPA or WPA2 enabled, a hacker must first sniff the WPA 4-way handshake. The user can be elicited to provide this sequence by first forcing them offline with the deauthentication attack.
Current 802.11 standard defines "frame" types for use in management and control of wireless links. IEEE 802.11w is the Protected Management Frames standard for the IEEE 802.11 family of standards. Task Group w worked on improving the IEEE 802.11 Medium Access Control layer (MAC). Its objective was to increase security by providing data confidentiality of management frames, mechanisms that enable data integrity, data origin authenticity, and replay protection.
In January 2018, the Wi-Fi Alliance announced WPA3 as a replacement to WPA2.
Protection of management frames as specified in the IEEE 802.11w amendment is enforced by the WPA3 specifications.
SAE is a variant of the Dragonfly Key Exchange defined in RFC 7664, based on Diffie–Hellman (DH) key exchange using finite cyclic groups which can be a primary cyclic group or an elliptic curve. The problem of using Diffie–Hellman key exchange is that it does not have an authentication mechanism. So the resulting key is influenced by a pre-shared key and the MAC addresses of both peers to solve the authentication problem.
In cryptography, forward secrecy (FS), also known as perfect forward secrecy (PFS), is a feature of specific key agreement protocols that gives assurances that session keys will not be compromised even if the private key of the server is compromised.
Opportunistic Wireless Encryption (OWE) is an extension to IEEE 802.11 which adds a standard for opportunistic encryption for use with an open Wi-Fi network. OWE is an encryption technique similar to that of Simultaneous Authentication of Equals (SAE) and is specified by Internet Engineering Task Force (IETF) in RFC 8110 with devices certified as Wi-Fi Certified Enhanced Open by the Wi-Fi Alliance.