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Subnet change, DHCP help

I am in the process of changing our subnet from a /20 to a /19 to make way for a large influx (2000+) of new PC’s coming in.  All routers, firewalls, switches have been changed to the new subnet already.  My last step is to change servers and DHCP.  Currently we run a network, to are static, and plenty of room for static's.  DHCP pool starts at to and is nearing capacity.  

As for DHCP, what would be the best approach to add more addresses to the DHCP pool with the new subnet.  I’ve read a few things:
1. Doing a 80/20 split with another server and set a delay on the second one to prioritize
2.Delete the current scope and recreate with a wider address pool
3. Keep the current scope and create a super scope

I’m leaning towards just deleting the current scope and recreating with a to address pool.  Thoughts?  Do I need 2 DHCP servers?
Internet ProtocolsDHCP

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8/22/2022 - Mon


I would consider deleting the current scope and recreating it based upon your new IP address pool.  If you go with 2 dhcp servers, there is potential for conflict.

Some would say that you have too many hosts as it is.  Doubling from there seems risky from a traffic point of view.  Only you can know but these are really big numbers!!

But, strictly from a technical point of view, I see no reason to not simply change the subnet mask and add an appropriate number of DHCP addresses at the DHCP server setup.
So, if you have:  /
and give the DHCP server 6400 addresses starting at then that seems consistent with the approach you intend to follow.

But, one might observe:
You currently have around 1279 static addresses available and that's "OK".
You currently have around 2815 dynamic addresses available and that's not "OK".
Do you really have that many hosts?  Or is maybe your DHCP pool being overtaken by lease times that are too long and lots of transient device activity?  If the latter, I would set the lease time at 8 hours or maybe even less if the transient activity is higher than 1-time each day appearances.
Anyway, you plan to end up with a total of 6900 dyamic addresses???  wow.

You probably will want to split things up into subnets that are smaller and route between them.  But let's make sure the requirements are clear first.  Just how many simultaneous hosts are operating?

There will be a lot of hosts, we currently have around 2500, and will be adding another 2500 in the coming months, We will be going 1 to1 with employees and laptops in the coming months on top of what we currently have.  We'll be around 5k dhcp hosts when its all said and done.  

So i was just trying to evaluate the best route to take, if 1 DHCP server will  handle that or if I am better off splitting it up between 2 to load balance.
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