creating a new domain on the same IP range as a pre existing domain

Posted on 2009-02-12
Last Modified: 2013-11-30
The company I've just joined are all on a workgroup using the DHCP of an already existing domain (dif company but the bosses of both are related... )

They need their own domain, quickly so I know this is the "quick and dirty" way of doing it but as we dont have our own internet connection I was looking to do a DCPROMO on the 2008 server we have set up as a file share, create it as a DC on a new domain, setting up DNS and leaving the DHCP same as is. Then setting up my users in AD and migrating them off the work group and onto my domain.
My concerns are whether or not there will there be a problem with mulitple domains using the same DHCP and that in my ignorance i'm missing something/not doing something I should and if it all goes wrong... will I be able to demote the file server back to its original state and wait for the purchase of our own line/router/firewall

Could someone point out the holes in my plan please


Question by:deanvanrooyen
    LVL 9

    Accepted Solution

    You can have the DHCP server off the windows server, but it would prefer to have control over the DHCP, so yes the first part will work.  Once you have promoted the server to be AD and then want to demote it you will first have to either get another server to act as the AD server, or put everyone back on a workgroup.  I would try to avoid doing the second.

    The other option is to put all the users on the same AD server and just use file permissions to control access for the 2 different groups.  That way Windows has control over DNS and DHCP and so is happier.
    LVL 18

    Assisted Solution

    Your plan should work, which means you can have multiple domains on the same network.
    But if I were you, I would set up your network in a completely address space, either configure your server a multi-homed and run as a router, or just buy another cheap router (like Linksys, Dlink, etc) and seperate the two networks as it maybe a management headache to have two companies network sharing the same address space.
    LVL 12

    Author Closing Comment

    Cheers Guys, thanks for your input... I think running with my plan as is would be too quick and temporary so im going to opt on the cheap router option and ensure we're at least on a seperate subnet...

    Thanks again


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