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I'm a novice in networking and was wondering if this is possible. If so, how is it done?

Through my research, the DHCP server can do this job by pinging the IP address first to check if it is already taken before leasing it to a workstation.

Any help would greatly be appreciated!

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Why do you want to do this? –  cpast Jan 30 '13 at 3:28
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To avoid IP conflicts? –  tray Jan 30 '13 at 3:36
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What I meant was: If there's a DHCP server, you can just use that, right? If you want to use a static IP, why would there be a conflict? When you manually assign addresses, preventing a conflict is as easy as not assigning two computers the same address (once the static IP is set up, you shouldn't need to change it) –  cpast Jan 30 '13 at 3:40
    
Thanks for the clarification. Is it possible to assign a static IP address to a workstation and accidentally have the DHCP server assign that same static IP address to another workstation? –  tray Jan 30 '13 at 3:44
    
I believe that that can only happen if the workstation isn't connected to the network at the time. Even so, you can change the DHCP server's range, and make the static IP outside that range (this is what I do with printers at my house: DHCP ends at 192.168.0.99, printers are around 192.168.0.150) –  cpast Jan 30 '13 at 3:46

3 Answers 3

up vote 4 down vote accepted

There are several things:

  • DHCP will do that on the router. You do not have to worry about it, provided all components on the network are set to DHCP, too, or have fixed IP addresses that are outside of the DHCP range. So if you set your router to assign 192.168.1.1-125, you can use 126-255 for the last digit for manually assigned IP addresses.
  • Windows will generally complain if there is a IP address conflict in the network with the current machine. It can be that other OS like linux or OSx do that too, but I am not sure. I would recommend you to ask in a separate question.
  • There are routers where you can, on top of DHCP assign specific IP addresses to specific machines, such as a network printer or file servers to avoid different IPs during router restarts. DLink routers for example can do that.
  • If you assign the IPs manually, you will have to manually check that the components do not use the same IP address. If you assign the same IP to a network printer and a NAS, you might have trouble since they do not have a OS like windows that can warn the user.
  • The admin panel of your router should show you the currently assigned IP addresses. Like that you can check which ones are free.
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That should be 255 for the last octet, not 256. –  cpast Jan 30 '13 at 3:50
    
@cpast of course! fixed it! –  uncovery Jan 30 '13 at 4:17
    
It might be less typing to assign 192.168.2.x to the DHCP server and use 192.168.1.x for yourself. The private range is 192.168.[0-255].[0-255], 65535 addresses. –  MSalters Jan 30 '13 at 13:36

On a regular boot it's the OS who initiates the DHCP transaction for getting an IP, It is also the OS who might have provisions (i.e. Windows) for detecting a duplicated IP address (packets with the same IP having different source MAC addresses). If possible you should avoid fixed IP, if not possible you should carefully plan your DHCP server IP range avoiding collisions between dynamic and static IP assignations.

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You should manage and document your IP addresses as best practice, so you could have a look and determine if you can assign that address.

You should reserve/exclude some addressing space for static assignments at DHCP server too, as conflicts can happen if the workstation comes online while its address is already given by DHCP to some other host.

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