strange DHCP error: "192.168.2.2 in use by..."

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Level 1

35 points

strange DHCP error: "192.168.2.2 in use by..."

A strange error popped up on my Desktop today, for no particularly obvious reason, and which I do not understand:

"192.168.2.2 in use by 00:0e:35:43:4c:dc, DHCP Server 192.168.2.1"

I am connected wirelessly to a router, and also have Windows installed via Bootcamp on a separate partition. I am running a new 2 GHz MacBook Pro with MacOS X 10.4.7 with 2 GB of RAM, and other than intermittent connection issues (similar to "brown-outs") which causes my Internet connection to go down every so often, I am not having any other connectivity issues (as far as I know).

Please advise.

Thanks

MacBook Pro 2 GHz, Mac OS X (10.4.7), 2 GHz, 2 GB RAM

Posted on Sep 4, 2006 6:12 PM

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Answer 1

Sep 4, 2006 7:33 PM in response to blackbird

Can you tell what your IP address is?
And the IP address of your router? (usually 192.168.xx.1)

Have you added any devices on the network? Print Server, another computer, something? Is the router you connect to, under your control? Look at your DHCP table on the router and see who's connected.

Is your wireless connection encrypted using at least the WEP level of encryption? If not, this may mean that someone else is piggybacking a network connection to your router and somehow picked up that xx.xx.2.2 address that you had before.

You also might want to investigate these "brownouts"...but that's a subject for another topic.

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Answer 2

blackbird Author

Level 1

35 points

Sep 4, 2006 8:53 PM in response to Rick Van Vliet

Rick,

My security settings are: Security Mode set to WPA-PSK (no server); Encryption Mode is TKIP. How does that security mode compare to WEP?

No devices were added to the network as far as I know.

There are 3 IPs on my network, in addition to the Router: 192.168.2.3, 192.168.2.4 and 192.168.2.5 - and they're all accounted for. I think I figured out the culprit, though: The error showed that the probem IP, 192.168.2.2, was in use by the computer with a MAC address that matches the computer now using 192.168.2.4. So at least it doesn't look like somebody from outside the network sneaking in.

Thanks for your help!

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Answer 3

Sep 5, 2006 4:09 AM in response to blackbird

Hey blackbird --
WPA is better than WEP, (but WEP is better than nothing).

Glad everyone's accounted for. With DHCP addresses being handed out by the router, there may be times when you reboot different machines...that one machine will picked up an address that had been used by another.
Now...if a mac is sleeping, I believe that the DHCP server (router) will not see that IP address, and thus may hand it out to the machine in the preceding paragraph that gets rebooted, or switched 'on' after having been 'off' for a while.

When/if you get this frequently, you might want to assign static IP addresses to certain machines. If you're going to do any web-sharing over the internet, or do ftp hosting...static IP addresses are almost a "must" (If you're not going to do any of that hosting...then play it by ear with the static IP's).

Hope that helps. ("HTH")

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