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My organization uses the ISPs router to assign IP address to any devices that connect to the network. I am in the process of creating a domain controller, dhcp and dns server as well as have active directory setup. All these servers are a first for the organization, they’ve grown to big to remain the way everything is setup.

My question is first with DHCP. Right now we are using 192.168.0.x (again all devices get assigned an IP from the ISP router). I am configuring DHCP and setting up a new scope. Is it possible to keep the IP address range we have now and use that in the new scope? Or is it recommended to start a completely different scope of IP addresses (maybe 192.168.1.x)?

Any help will be great!

9 Spice ups
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You can do either. Just remember to turn off the ISP DHCP server when you turn on yours or they’ll both be giving out addresses which could cause trouble.

Personally I would go with something else because too many home networks use 192.168.x and if you end up with people wanting to VPN from home it can be a little harder to set up if they’re on the same scope.

6 Spice ups
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You could keep the same scheme, just make sure DHCP is off on the router when you do. After that it’s a normal DHCP configuration with the new server. Setup the server options, the scope options and authorize the service.

3 Spice ups
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If you do go with the same scope, you’ll have to either 1) shorten the leases issued on the current DHCP server ahead of time and/or 2) restart the computers after the new one is active. Else, you get ip conflicts until the leases expire. Not a big deal, and easy to fix, but something to be aware of.

2 Spice ups
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Yes please! 192.168.1.x should not be used if you are starting over.

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shouldn’t be but, will still work. The only time you will run into problems that I’m aware of is if you start doing VPN services for end users. If you don’t, not really a problem.

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Now its a matter of shutting DHCP off on the router. I’m only wanting to use the same IP address scheme to help with not changing so much.

1 Spice up
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Unless you have a bunch of stuff with static IPs why does it matter if you change?

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Why put yourself in that position if you don’t have to. It’s forward thinking - if I had a chance to do over on my own network I would not knowing what a PAIN it is to have to talk remote users to change the home router’s IP address to something like 10.10.10.1 - great fun when trying to do it with a FIOS connection. I’m just saying …

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I understand what you are saying and I’m not in 100% disagreement with you. But sometimes it’s best not to drastically change too much when implementing new technology as the OP is doing. Gradual changes over time are easier to swallow. You can eat an elephant one bite at a time…

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I could see using the same DHCP scope as the ISP-provided unit, at first. Make sure the transition is smooth. I would change to something else though, for all the reasons that have already been mentioned.

Also, you will end up keying in IP addresses a lot, for different reasons, set yourself up something easy! It looks like you have a /24 network, go with 10.0.0.X, make life easier for you in the long run. My 2 cents.

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Don’t use 192.168.x.x!! You can save a ton of hassle by going with 10 or 172.

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Where shall be the difference? There are tons of hassles in all of them.

BTW - usable adress ranges are:

10.0.0.1 to 10.255.255.254

172.16.0.1 to 172.31.255.254

192.168.0.1 to 192.168.255.254

Best is to stop the DHCP on ISP’s router, turn off the switch, start your own DHCP and turn on the switch again; every DHCP-device will show up with its actual DHCP address, everybody is fine and the network is back working.

Things are sometimes much easier than it seems.

1 Spice up