1. By Markus Kriechhammer
Wireless LAN
By Markus Kriechhammer

2. Wireless LAN - Overview
What is a wireless LAN (WLAN)
Devices
The most important standards
Security issues
Advantages / Disadvantages

3. What ist WLAN Wireless local area network
Ethernet-Frame are transmitted via „air“
Network-protocols can be TCP/IP, IPX/SPX and Apple Talk

4. Devices

5. The most important Standards
IEEE b
up to 11 Mbps, 2,4 GHz unlicensed, frequency shared
IEEE a
up to 54 Mbps, 5 GHz unlicensed, only in US
IEEE g
up to 54 Mbps, 2,4 GHz unlicensed, fs, compatible with b
IEEE i
extending wireless security features

6. Basic technology concepts
Frequency band
2.4GHz
5GHz
Max data rate
11Mbps
54Mbps
availability
Worldwide US
Interference sources
Cordless phone
Microwave oven
Bluetooth
Hiperlan
devices

7. Basic technology concepts
@100Mw
802.11a
@40Mw
802.11g
50 ft
11Mbps
54Mbps
100 ft
36Mbps
125 ft
12Mbps
150 ft
5.5Mbps
6Mbps
250 ft
2Mbps ?
350 ft
1Mbps

8. WLAN Modes (802.11b)
Ad Hoc is the term used to explain when a user is connecting to another b device directly without an access point. The user must decide what IP address and subnet to communicate.
Infrastructure is the term used to explain when a user is connecting to the wireless LAN using an Access Point. The Access Point or another network device can provide services like DHCP and NAT

9. Security issues All the normal Internet issues and more
Open WLANs are everywhere
Vendor defaults are usually open
Many types of attacks
Attackers can be miles away

10. Common WLAN Security Needs
Private – Homes
Information Security
Companies
Access Monitoring
Accounting
Firewall

11. Solving the security problems
Solve the problem at the application layer with encryption (e.g. ssh, ssl) and/or better authentication/authorization
(e.g. Kerberos, secur-id)
Solve the problem at the network level through link encryption (WEP, EAP) or VPN (IPSEC)

12. Example VPN Configuration

13. Advantages Disadvantages
Mobility
Cost advantages
Easy to install
Easy to integrate into existing networks
Weak native encryption
Default settings of manufacturers
Easy to „hack“
Configuration (vendor – depending)

14. References

15. Thank you