Quote:
Originally Posted by jammies
I have an excellent mental image of MoneyGuy blinking as he realizes he now knows less than he did before asking the question.
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Yep, I realized that as I was tying it, but was too busy for a complete response.
Yoy have a device on your network with a Static IP address, likely a printer etc. This address is set and never charges. Your DHCP hands out IP addresses within a certain range to all devices on the network that need an address (and don't have a static IP). The range it picks addresses from is set usually to something like 192.168.1.100 to 192.168.1.200, and it just keeps track of which addresses it has given out to which devices, but only for a little while (normally 8 days) , to make sure that it doesn't give out the same address to another device while this one is in use.
So what happens if someone doesn't know what they are doing, or doesn't have network documentation, they set a static IP for something like a printer, inside that DHCP range. In our example above, let's say 192.168.1.169. Now, when the DHCP server is giving out addresses, it has no idea that thus address is in use, so it will just assign this address to another device. Many computers will realize there is another device with the same IP address, and give you a warning like you saw.
The solution is to use a network scanning tool, like netscan, and determine which IP addresses are being used by which devices, and then see which of those addresses is not inside your DHCP scope (normally found on your server or router). You can then either change the static IP address to something that is not in use (and outside dhcp range, change the dhcp scope, or set a DHCP reservation for that device, so DHCP stops handing out that address.
Alternatively, you can go to each device and check which ones are static, and then either change the static ip to something outside the dhcp range, or set the network to use dhcp on that device.