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We currently have a pretty simple setup. We have a 2008 Windows Server using DHCP for our clients. We have a remote site that has 10 people. The remote site currently get their IPs from the router, but we'd like for them to get their IP from our local DHCP server here. From what i've read this seems fairly straightforward. On the remote router turn on Ip-helper x.x.x.x to point to the DHCP server back here. I guess my concern is, how will the transition go? If i enable that right now, will the users who currently have an IP lease from the router drop and acquire a new one, or will it just allow those leases to expire, then once they do, it will then look at the new IP range from the local DHCP server here? Just curious if this is anything i need to worry about or is it really as simple as it seems, just set it and run. I've configured RRAS on my side as well per several online articles discussing how to set this up. Thanks for any insight you can give!

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up vote 1 down vote accepted

Computers won't magically know that you switched over and request a new lease. It will wait until the lease expires. To stop this from being an issue, you should make sure that the address pools do not overlap. After you have the ip-helper entry in place and non-overlapping pools, you should turn off DHCP on the firewall there and all new lease requests will hit your server.

Keep in mind that having DHCP traverse a WAN via VPN probably isn't a great idea. It's an essential service. If your main office is down but your remote office is fine, users will have a problem. DHCP is lightweight. You could even get a cheapo old workstation, install a 2nd hard drive and use md for some cheap redundancy and run dhcpd on it, if you don't want to use a full blown Windows license for just DHCP.

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Thanks for the quick response. I kind of figured it would be fairly smooth with dropping leases from the old and reacquiring a new one from the server. I think our current way is working fine but my boss is wanting to try this way out, so i'll give it a shot. If we have any issues then i'll know exactly what to go back to. :) Thanks for your help! – Don Oct 4 '11 at 14:04

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