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While I know a bit about networking, I am more of a programmer, and I have never set up a DHCP server. I have always allowed a router to assign IP addresses. However, my boss has asked me to switch out our old Win2k Domain Controller and DHCP server to a new server. The catch is that he wants to just use our router to assign IP addresses rather than have the new server do it. Is this going to be more than just disconnecting the old server? And if so, are there any documents or tips anyone can help me to make the transition a bit smoother? The new server will most likely have Windows Server 2008 R2.

Any advice I can get on this matter would be greatly appreciated.

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It might help to know what kind of switch you have? – Chopper3 Feb 8 '11 at 15:20
up vote 3 down vote accepted

In a Windows domain this small, it's easiest (and possibly best) to have your DC be the DHCP server and DNS server. The latter (DNS) is essentially required, and DHCP is pretty easy to manage with the built-in Windows server tools.

What business or technical need would be met by having DHCP served from the router as opposed to the server?

Not to get to deep into it in this question, but are you adding the new server to you existing domain, moving the FSMO roles, and then removing the old server from the domain, or are you making a whole new domain on the new server? If you do the latter (new domain), you'll have to migrate all your fileshares (with permissions), re-do all the users and groups, and migrate all the workstation profiles. Not a fun task, and best to be avoided.

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The new server is going to handle the same things the current one does, e.g. DHCP (see comment on mcr's response below), AD, DC, SVN Repositories, etc. I am going to post a new question relating to migrating those settings over. – Alexander Miles Feb 8 '11 at 17:03

If the network is small, shouldn't be too much of a hassle. If the old server was just DHCP, leave it on and just turn off the DHCP service, and set up the new router (you could do that even if it was running other services as well). That way if something doesn't work with the new router, you can just right click the service and start it back up in the quick.

The main thing you want to look out for is existing ranges, reservations, and exclusions on your current DHCP box, and make sure you copy those settings to the new router.

Also, depending on how long your leases are, you might want to increase them and let them take effect before the transition, so you have more time to switch over.

Also, make sure you have your client PCs registering their IPs to their DNS server.

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This is also a valid answer. In a small network, it's not a big thing, mostly a matter of preference and ease of operations/maintenance. – mfinni Feb 8 '11 at 15:44

Ensure you copy all reservations over, then shorten the lease time on the old server.

At some point, you can start splitting the scope into two smaller scopes and enable both DHCP servers. Then once you see everything works fine you can grow the scope on the new DHCP server and make it smaller on the other end.

Or if it's a pretty small office just do it all at once and tell anyone having issues to reboot or renew.

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I think the other question is whether or not your old machine is a PDC only, or if you are also doing ActiveDirectory. If you are using AD, it really likes to be the DHCP server so that it can keep forward and reverse DNS up to date. (This becomes even more convenient once you install IPv6). If the reason you want to do this is so that you can segment your network, and your router is not of the Linksys home router variety, you may find that having your router configured as a DHCP relay, with the windows machine as the actual DHCP server is a good compromise. Also, I'd want to know what your router is.

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I'm sorry, can you clarify what you mean by this? If you have a DC, then by definition you have an Active Directory. – mfinni Feb 8 '11 at 16:08
AD will be active on the server, and judging from the other answers as well, I think I am going to keep the DHCP server on the new Windows Server. – Alexander Miles Feb 8 '11 at 17:00
In the 2000 days, you didn't have to run AD, you could run the old workground stuff. – mcr Oct 31 '11 at 18:55

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