Hi Ted,
On Mon, Oct 01, 2007 at 02:50:32PM -0700, Ted Crum wrote:
> Two of our Mac users (OS 10.4.10) are getting this error message
> while operating on the wired network, but while in an AirBears zone
> and presumably with the radio on. It does not interfere with their
> work once it is dismissed:
>
> 136.152.128.112 in use by 00:04:23:bd:73:20, DHCP Server 169.229.252.130 .
>
> The AirBears IP address and MAC address vary.
It is hard to say with any degree of certainty what is causing the
above error message as there are several key bits of information
missing from the above report. If you would like further investigation
to occur, please open a trouble ticket by sending an email
message to the service desk at servicedesk_at_berkeley.edu. Be sure to
send the above information and include the exact error messages on
both devices, the date and time when each error messages
occurred and the IP and mac addresses of the devices with the error
messages.
The most likely explanation is that a device with the above MAC
address, 00:04:23:bd:73:20, used the IP address 136.152.128.112
without the permission of the DHCP server. This sometimes happens when
a device (device 1) at one time had a valid lease for IP address A on
network Z and subsequently disconnects from network Z. When device 1
reconnects to network Z, it may try to use IP address A from the last
time it was connected to network Z. This behavior causes a conflict if
IP address A is in use by another device, device 2, also on network
Z. The conflict will eventually resolve itself when device 1 tries to
renew its expired lease for IP address A. The DHCP server offers a
lease for a different IP address as IP address A is already in use by
device 2. device 1 accepts this lease and changes its IP address,
resolving the conflict with device 2.
If an IP conflict with the same MAC address persists, open a trouble
ticket.
> I'm sure they would not see the message if they turned their radios
> off, but Meatball doesn't work that way. Is this a result of AirBears
> congestion, or of a method of reducing congestion that throws idle
> radios off the island?
We have seen a steady increase in the number of wireless devices on
campus. When devices are connected to both the wired and wireless
networks, they often obtain an IP address via DHCP on the wireless
network even though they use only the wired network exclusively while
connected to it. This behavior wastes IP address space, a scarce
commodity both on campus and on the Internet. We do not currently have
any way to avoid this needless consumption of resources; some options
are being explored. It is always helpful to disconnect from AirBears
when you are using the wired network if your device does not
automagically do this for you.
Erik
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Received on Tue Oct 02 2007 - 07:33:46 PDT
This archive was generated by hypermail 2.2.0 : Tue Oct 02 2007 - 07:33:54 PDT