Since the attack on WEP is based on statistical analysis, rotating the keys does help somewhat.. It all depends on the traffic level on the network...

I see no reason why Kerberos would be weakened when over wireless: Kerberos isn't vulnerable to sniffing on a shared network (not swithced, ie: on a hub). Kerberos is actually pretty cool when you study it a bit; if anyone's intereseted, check out the files attached one's pretty cool and light, the other on more technical / heavy...

You could use IPSec over your wireless network...

Cisco has some additionnal security built-in their access points and wireless NICs but you have to use their solutions end-to-end...

Ammo