Lossing IP addresses

[bozemans]

I know I misspelled "Lossing"....dang it.....

We are experiencing a situation where our new MBA fail to keep the same IP address after we deployed them this last week. They continually receive an error message about someone else using their IP address. I used a policy that ran after the image was completed to add the local Wifi connection information. However, now I am wondering if this policy could be causing this issue that we are facing. We have been able to track down a "rouge" device that is "acquiring" between 75 - 100 of our IP address at the same time. Our IT dept. has cleared all of the old IP address from 2009 MB that are no longer in circulation, but we continue to have the same issue. Could a policy I created and placed on each of the laptops create this issue? If not, any ideas on how to find a rouge device that "steals" your IP address? Anyone have any ideas?

13' MBA Early 2014
OSX 10.9.4
JSS 9.3

[mm2270]

Are you using static IP assignments? Just curious why that would be necessary if that's the case.

[bozemans]

Forgive my ingonarance but, in the past our 2009 would acquire an IP address from our available list, go through an auto set up and then keep that address for the rest of the year/life of the client. My IT dept. tells me that we have static for copiers and servers only.

[tron_jones]

Can you do a Lookup on the ip and see the ip's dns name using "Network Utility"?

[htse]

examine the ARP cache when it occurs, that should get you the offending system, or at least it's MAC address, that should help you narrow down possible systems.

[htse]

Do any of them contain scripts that might refer to network devices en0 or en1? The naming schema for a MacBook Air is different than a MacBook, with the MacBook AIr Wi-Fi claiming en0, en0 is the Ethernet and en1 is the Wi-Fi on a MacBook.

[Look · Accepted solution]

If they are getting their IP's through DHCP there may be an unintentional or misconfigured DHCP server giving out duplicate addresses on the same subnet.

[bozemans]

Ok, so we discovered that the script we sent out in the image set the DHCP as the name of our wireless network on the /Network/Wifi/Advanced/TCP/IP(Tab)/DHCP Client ID. This was causing everyone of our clients to replicate or acquire multiple IP addresses. We sent our a script to take away this flaw and now we are back up and going.