I changed the wireless card in my m0n0wall 1.1 box from a dlink 500 to a
dlink 650, then rebooted.
A couple of days later I notice this weirdness in syslog:

Dec 1 12:59:29 /kernel: arp: 00:60:08:35:bb:95 is using my IP address
10.28.1.1!
Dec 1 12:59:29 /kernel: arp: 00:05:5d:25:29:83 is using my IP address
10.28.1.1!

Now, arp on an internal linux box claims:
Address                  HWtype  HWaddress           Flags Mask     Iface
m0n0wall.criggie.dyndns  ether   00:60:08:35:BB:95   C              eth0

An interesting symptom - the windows XP box on the lan can connect to
m0n0wall's IP but not the hostname.  A linux box can connect to both the IP
and the hostname.

Here's the sections from the m0n0wall's interfaces page:
WAN interface
Status up
MAC address 00:60:97:dd:95:8d
IP address 202.999.999.999
Subnet mask 255.255.255.0
Gateway 202.999.999.1

LAN interface
Status up
MAC address 00:60:08:35:bb:95
IP address 10.28.1.1
Subnet mask 255.255.0.0
Media 100baseTX <full-duplex>

Wireless interface
Status associated
MAC address 00:05:5d:25:29:83
IP address 10.29.1.1
Subnet mask 255.255.0.0
Channel 6
SSID criggie.dyndns.org
In/out packets 12650/290 (1.08 MB/17 KB)
In/out errors 0/0
Collisions 37
  (this wireless link isn't used for anything yet.)

CLUG horse interface
Status up
MAC address 00:60:08:a1:12:11
IP address 192.168.1.1
Subnet mask 255.255.255.0
Media 100baseTX <full-duplex>
  (this is a ghetto-hosted machine on its own interface)

Garage interface
Status up
MAC address 00:60:08:a1:12:3e
Media 100baseTX <full-duplex>
 (this is bridged with lan)


What has happened?  Do I have a corrupt arp table somewhere?  Did the change
of wireless NIC do this (seems doubtful.)