Novell LINUX ENTERPRISE SERVER 10 - INSTALLATION AND ADMINISTRATION 11-05-2007 Installation Manual page 556

Security
If you want to set up a wireless network, remember that anybody within the transmission
range can easily access it if no security measures are implemented. Therefore, be sure
to activate an encryption method. All WLAN cards and access points support WEP
encryption. Although this is not entirely safe, it does present an obstacle for a potential
attacker. WEP is usually adequate for private use. WPA-PSK would be even better, but
it is not implemented in older access points or routers with WLAN functionality. On
some devices, WPA can be implemented by means of a firmware update. Furthermore,
Linux does not support WPA on all hardware components. When this documentation
was prepared, WPA only worked with cards using Atheros, Intel PRO/Wireless, or
Prism2/2.5/3 chips. On Prism2/2.5/3, WPA only works if the hostap driver is used (see
Section "Problems with Prism2 Cards" (page 538)). If WPA is not available, WEP is
better than no encryption. In enterprises with advanced security requirements, wireless
networks should only be operated with WPA.
29.1.6 Troubleshooting
If your WLAN card fails to respond, check if you have downloaded the needed firmware.
Refer to Section 29.1.1, "Hardware" (page 530). The following paragraphs cover some
known problems.
Multiple Network Devices
Modern laptops usually have a network card and a WLAN card. If you configured both
devices with DHCP (automatic address assignment), you may encounter problems with
the name resolution and the default gateway. This is evident from the fact that you can
ping the router but cannot surf the Internet. The Support Database features an article
on this subject at
http://en.opensuse.org/SDB:Name_Resolution_Does
_Not_Work_with_Several_Concurrent_DHCP_Clients.
Problems with Prism2 Cards
Several drivers are available for devices with Prism2 chips. The various cards work
more or less smoothly with the various drivers. With these cards, WPA is only possible
with the hostap driver. If such a card does not work properly or not at all or you want
538 Installation and Administration