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Wireless LAN, WLAN Security, and VPN

Wireless LAN, WLAN Security, and VPN. 麟瑞科技 台南辦事處 技術經理 張晃崚. WLAN & VPN FAQ. What is WLAN?802.11a?802.11b?802.11g? Which standard (product) should we use? How to deploy WLAN? How to block intruders? How to authenticate users? How to keep data secure? What is roaming?

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Wireless LAN, WLAN Security, and VPN

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  1. Wireless LAN, WLAN Security, and VPN 麟瑞科技 台南辦事處 技術經理 張晃崚

  2. WLAN & VPN FAQ • What is WLAN?802.11a?802.11b?802.11g? • Which standard (product) should we use? • How to deploy WLAN? • How to block intruders? • How to authenticate users? • How to keep data secure? • What is roaming? • How to provide a fast path for some VIP users? • How to exchange data securely between offices?

  3. Agenda • Introduction to Wireless LAN • WLAN deployments • WLAN security issues • WLAN security solutions • VPN solutions

  4. Agenda • Introduction to Wireless LAN • WLAN deployments • WLAN security issues • WLAN security solutions • VPN solutions

  5. What is Wireless Network • Wireless Network: • 802.11x standards (Wi-Fi) • Cell phones • Bluetooth • HomeRF • Fixed Broadband wireless, IEEE 802.16 • Mobile broadband • Optical point-to-point wireless

  6. What is Wireless LAN • IEEE 802.11-based networks • Bluetooth is regarded as a PAN (Personal Area Network) • Need Wireless NIC and Access Point(AP)

  7. Wireless LAN vs. Wired LAN Wireless LAN Wired LAN CSMA/CA Media Access CSMA/CD -10 Bit error rate 0.1% 10 Duplex half half/full Speed slow fast Throughput Reduce 50-60% N/A

  8. Wireless LAN vs. Wired LAN • All 802 WLANs employ handshaked transmission to compensate • WLAN just like PUSH-to-TALK radio • WLAN will be a step backward: slower speed, half duplex, shared media. • BUT, gain FREEDOM • AP usually is a Layer 2 bridge (between wired LAN and wireless LAN) • Spanning Tree Protocol issue

  9. Wireless LAN Standards 802.11b 802.11a 802.11g Frequency 2.4 GHz 5 GHz 2.4 GHz Channel 3 8 3 Max speed 11Mbps 54Mbps 54Mbps Real throughput 4-6 Mbps 22-27 Mbps 22-27 Mbps Interference Yes No Yes Distance for max speed 120-140 ft. 1-2 ft. 120-140 ft. 120-140 ft. 60 ft. ??? ft. Distance for half speed Maturity Very mature Early No product

  10. 802.11b+ • IEEE 802.11g will be finalized in May 2003 • Not a formal IEEE specification • Texas Instruments (TI) applied PBCC to enable 22Mbps data rate • Interoperable with 802.11b device at 11Mbps • Must use TI’s chip to enable 22Mbps

  11. Other 802.11x standard • 802.11d: Multiple regulatory domains • 802.11e: QoS • 802.11f: Inter-Access Point Protocol (IAPP) • 802.11h: Dynamic Frequency Selection(DFS) and Transmit Power Control (TPC) • 802.11i: Security

  12. Which Technology should you use? • Decision should be based on requirements of system/users • User bandwidth requirements • User density • Overall implementation cost • Upgrade requirements • Client availability • Client platform features

  13. Agenda • Introduction to Wireless LAN • WLAN deployments • WLAN security issues • WLAN security solutions • VPN solutions

  14. Typical WLAN Topologies Wireless “Cell” Wireless “Cell” Channel 1 Channel 6 LAN Backbone Access Point Access Point Wireless Clients Wireless Clients

  15. Wireless Repeater Topology Wireless Repeater “Cell” Channel 1 LAN Backbone Channel 1 Access Point Access Point Wireless Clients

  16. Hot Standby LAN Backbone Monitored AP Standby AP Wireless Clients

  17. Multi-rate Implementations 2 Mbps 2 Mbps 2 Mbps 2 Mbps 2 Mbps 5.5 Mbps 5.5 Mbps 5.5 Mbps 5.5 Mbps 5.5 Mbps 11 Mbps 11 Mbps 11 Mbps 11 Mbps 11 Mbps 11 Mbps 11 Mbps 11 Mbps 11 Mbps 11 Mbps 5.5 Mbps 5.5 Mbps 5.5 Mbps 5.5 Mbps 5.5 Mbps 2 Mbps 2 Mbps 2 Mbps 2 Mbps 2 Mbps

  18. Vendor Offering • Higher and variable transmission power • External antennas • Little throughput degradation with encryption • Line-power via the wired Ethernet cable • Dual-band: 802.11b + 802.11a • AP load balancing • Roaming between IP subnets • Hot Standby AP • VLAN support • Lockable case • Enhanced security features: 802.1x, 802.11i draft, etc.

  19. Agenda • Introduction to Wireless LAN • WLAN deployments • WLAN security issues • WLAN security solutions • VPN solutions

  20. WLAN Security Issues • Wireless is like having an RJ45 jack in the parking lot • Need to deny access to intruders • Need to secure message with good encryption technology

  21. WLAN Security Issues • Managing the security side of you networks requires several things • Protecting the ‘network’ from intruders • Requires authentication for users • Protecting the Wireless DATA from sniffers • Requires some type of encryption • Protecting you RF networks from being detected • The ability to MANAGE you users credentials • Includes WEP keys, users names, passwords, etc. • Protecting your wireless infrastructure from improper configuration • Required a good user manager interface on APs

  22. WLAN Security Issues • Managing the security side of you networks requires several things • To dynamically assign user’s IP address, gateway, etc. • Deploy DHCP server • To let roaming users be authenticated by their original account and passwords • Requires authentication roaming features for authentication servers

  23. Agenda • Introduction to Wireless LAN • WLAN deployments • WLAN security issues • WLAN security solutions • VPN solutions

  24. Authentication Techniques • Open System Authentication • No security • SSID Authentication • SSID is broadcast in clear text form • Can be obtained by snooping on traffic • Shared key Authentication (WEP) • Key stolen • Employee leaves

  25. Authentication Techniques • MAC address Authentication • MAC is sent in clear form • Can be obtained be snooping • Attackers may change their MAC to match • Not flexible and scalable • 802.1x and Extensible Authentication Protocol (EAP) • Secure not only client but also devices • Only Windows XP and few vendors support this technique

  26. Authentication Techniques • VPN client Authentication • Does good authentication and encryption • Variable authentication and encryption method to choose • Need VPN client software installed • Wireless Gateway Authentication • No need to install any client software • Pop up authentication window when initiating connection (use web browser) • Easy to install and configure • One wireless gateway for a subnet

  27. Wireless Gateway Topology

  28. Blocking Inter-client communication • PSPF—Publicly Secure Packet Forwarding • Prevents WLAN inter-client communication • Relies on MAC address • Same subnet devices only

  29. Encryption Techniques • Key Management • Can be painful • Requires a power tool to manage keys • Easy to hack with well-know single key • Key Rotation • Changing the user’s key periodically • Broadcast Key Rotation • WEP Encryption • 128 bit WEP • IPsec

  30. Encryption Techniques • IEEE 802.11i • TKIP (Data Integrity) • MIC (Data Integrity) • AES (Encryption) • Not yet complete

  31. WLAN Security Solution Product • Wireless Gateway • Bluesocket • Vernier • ReefEdge • VPN • Cisco VPN concentrator/router/client • NetScreen • Authentication Server • Cisco ACS (RADIUS, TACACS, LEAP) • RADIUS

  32. WLAN Security Solution Product Campus switch DHCP&AAA Server Wireless Gateway (Bluesocket) Or VPN Gateway (Cisco/NetScreen) Cisco Aironet 1100 (802.11b, 802.11g) Mobile IP VLAN Cisco Aironet 1200 (802.11a, 802.11b, 802.11g) External Antenna

  33. Cisco Aironet 1200 AP • Modular platform for single or dual band operation • Field upgradeable radios • Modular design enhances future upgrade ability • Simultaneous dual radio operation • 10/100 Ethernet LAN uplink

  34. Cisco Aironet 1100 AP • VLAN support • 802.11b, 802.11g (2.4 GHz)

  35. Bluesocket Wireless Gateway

  36. Agenda • Introduction to Wireless LAN • WLAN deployments • WLAN security issues • WLAN security solutions • VPN solutions

  37. VPN Type and Applications Type Application As Alternative To Benefits Dedicated Dial ISDN RemoteAccess VPN Remote Dial Connectivity Ubiquitous Access Lower Cost Site-to-Site Internal Connectivity Leased Line Frame Relay ATM Extend ConnectivityIncreased Bandwidth Lower Cost Site-to-Site VPN Fax Mail EDI Biz-to-Biz External Connectivity ExtranetVPN Facilitates E-Commerce

  38. VPN Type and Applications POP Central Site Extranet Business Partner Mobile User Internet VPN DSL Cable Home Telecommuter Site-to-SiteRemote Office

  39. Remote Access VPN Cisco VPN Clients Microsoft Win 2000 (IPSec) Microsoft Win 9x/NT (PPTP) WAN Router PIX Firewall Cisco VPN 3000 Concentrator Cisco Secure ACS (AAA) Telecommuter Internet VPN POP Central Site Mobile Customer

  40. Site-to-Site VPN Remote Campus Main Campus Remotel Campus Internet Small Office/ Home Office

  41. Extranet VPN Remote Office Supplier ISP Gateway Firewall Security Server Supplier ISP Network DMZ Corporate Intranet

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