From: "Lloyd Palfrey" <Lloyd at wsufftrust dot org dot uk>

> I am using MAC address RADIUS authentication for captive portal and I
> keep getting the following in the logs.

> Nov 21 11:22:38 /kernel: arp: 172.16.3.175 moved from 00:12:f0:ca:d0:71
> to 00:12:17:a9:9c:80 on sis0

> 00:12:17:a9:9c:80 Doesn't exist in the radius server.

> Anyone got any suggestions?

> Many Thanks

First, what is your topology?  Do you have things behind APs that use the 
APs MAC?  Could you have a user "borrowing" IP addresses?  Could a given 
user be swapping NICs?

                                Lee