Questions and Answers
FlexConnect APs can operate in either Connected mode or Standalone mode.
True
In Standalone mode, the FlexConnect AP can perform all CAPWAP functions.
False
Direct-Sequence Spread Spectrum (DSSS) is a modulation technique primarily used by 802.11a devices.
False
Frequency-Hopping Spread Spectrum (FHSS) requires synchronization between sender and receiver.
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Channel saturation can degrade the quality of wireless communication.
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Orthogonal Frequency-Division Multiplexing (OFDM) uses only a single frequency channel.
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Cisco offers techniques to mitigate frequency channel saturation.
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DSSS and FHSS are both modulation techniques used to avoid interference in wireless communications.
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In a man-in-the-middle attack, the hacker acts as a legitimate entity between two parties.
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The 'evil twin AP' attack uses a different SSID from the legitimate access point to deceive users.
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In Connected mode, the FlexConnect AP cannot switch client data traffic locally.
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The original 802.11 standard did not use Frequency-Hopping Spread Spectrum (FHSS).
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Identifying legitimate devices on a WLAN is unnecessary for defending against MITM attacks.
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MAC address filtering is a method used to enhance WLAN security.
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Open authentication is a type of secure authentication system for wireless networks.
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Authentication and encryption systems are integral components of secure WLANs.
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To defeat a MITM attack, network monitoring is the only required step.
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SSID cloaking involves hiding the network name from users.
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A rogue Access Point (AP) does not need to match the SSID of a legitimate AP to be considered a threat.
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Monitoring the traffic on the network can help identify unauthorized devices.
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WLAN networks operate in the 2.4 and 5 GHz frequency bands.
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The organization responsible for regulating satellite orbits is the Wi-Fi Alliance.
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IEEE is involved in specifying how a radio frequency is modulated for information transmission.
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The 2.4 GHz band corresponds to the SHF frequency range.
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The Wi-Fi Alliance aims to improve the interoperability of products based on the IEEE 802.11 standard.
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The IEEE 802 LAN/MAN family of standards is maintained by the International Telecommunication Union.
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WLAN devices exclusively operate on the frequency of 5 GHz.
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The electromagnetic spectrum includes the frequencies utilized by wireless devices.
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WPA uses the Advanced Encryption Standard (AES) for encryption.
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The RADIUS server requires the user's authentication information.
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WPA3 is considered less secure than WPA2.
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UDP port 1812 is used for RADIUS Authentication.
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TKIP encrypts the Layer 2 payload without using WEP.
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The shared key in RADIUS authentication is used to decrypt the messages.
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The Counter Cipher Mode with Block Chaining Message Authentication Code Protocol is used by WPA.
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WPA3 offers improved security features compared to WPA2.
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UDP ports 1645 and 1646 are the only ports used by RADIUS servers.
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802.1X standard ensures centralized authentication of end users.
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WPA3 - Enterprise requires the use of a 192-bit cryptographic suite and employs 802.1X/EAP authentication.
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Opportunistic Wireless Encryption (OWE) is used to provide authentication in Open Networks.
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WLAN networks can only operate in the 5 GHz frequency band.
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Simultaneous Authentication of Equals (SAE) helps protect against brute force attacks in WPA3 - Personal.
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DTLS is a protocol that provides encryption between access points (AP) and wireless controller (WLC).
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Study Notes
Wireless Radio Frequencies
- Wireless devices operate within the electromagnetic spectrum, specifically in the 2.4 GHz (UHF) and 5 GHz (SHF) frequency bands.
- WLAN standards include 802.11b/g/n/ax for 2.4 GHz and 802.11a/n/ac/ax for 5 GHz.
Wireless Standards Organizations
- ITU: Regulates radio spectrum allocation and satellite orbits.
- IEEE: Specifies modulation techniques and maintains IEEE 802 LAN/MAN family of standards.
- Wi-Fi Alliance: Promotes WLAN growth and product interoperability based on the 802.11 standard.
CAPWAP Operation
- FlexConnect allows AP configuration over a WAN link with two main modes:
- Connected mode: AP has CAPWAP tunnel connectivity with WLC, performing all functions.
- Standalone mode: AP operates without WLC connection, handling data traffic and client authentication locally.
Channel Management
- Channel saturation occurs when wireless demand exceeds capacity, degrading communication quality.
- Mitigation techniques include:
- DSSS: Spreads signal over larger frequency bands to avoid interference.
- FHSS: Rapidly switches carriers among frequency channels, requiring synchronization.
- OFDM: Uses multiple sub-channels on adjacent frequencies, improving efficiency.
WLAN Threats
- Man-in-the-Middle Attack (MITM): An attacker intercepts communication between legitimate entities. Commonly executed via "evil twin AP" attacks.
- Prevention strategies include authenticating devices and monitoring for abnormal network traffic.
Secure WLANs
Security Measures
- SSID Cloaking and MAC Address Filtering protect network access.
- Authentication systems include Open and Shared Key Authentication.
Encryption Methods
- WPA and WPA2 use TKIP (for legacy support) and AES (provides robust encryption) respectively.
- TKIP encrypts the Layer 2 payload, while AES relies on CCMP for data integrity.
Authentication in the Enterprise
- Requires a RADIUS server for AAA, mandating:
- RADIUS server IP address.
- UDP ports (1812 for Authentication; 1813 for Accounting, also 1645/1646).
- Shared key for device authentication.
WPA3 Features
- WPA3 replaces WPA2 as a more secure protocol:
- WPA3-Personal: Prevents brute force through Simultaneous Authentication of Equals (SAE).
- WPA3-Enterprise: Uses 802.1X/EAP, mandates a 192-bit cryptographic suite.
- Open Networks: Enforces Opportunistic Wireless Encryption (OWE) for traffic encryption.
- IoT Onboarding: Employs Device Provisioning Protocol (DPP) for rapid IoT device integration.
Summary of Wireless LANs
- WLAN types include WPAN, WLAN, WMAN, and WWAN, utilizing unlicensed radio spectrum.
- Standard protocols like CAPWAP manage multiple APs through a central controller.
- Wireless LAN devices operate using transmitters and receivers aligned to specific radio frequencies, employing DSSS, FHSS, and OFDM channel techniques for communication.
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Description
Explore the fundamentals of wireless radio frequencies, including 2.4 GHz and 5 GHz bands. Learn about major wireless standards organizations such as ITU and IEEE, as well as the CAPWAP operation modes. Understand channel management techniques to optimize communication quality.
