windows server 2012

mkramer777
mkramer777 used Ask the Experts™
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Starting to learn a bit more about DHCP and I have a quick question.  If I setup an exclusion range of ip addresses do these addresses get removed from distribution AND use or just distribution?  I want to pull out 10 addresses for 10 wifi access points I am setting up.
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JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018

Commented:
If you set up Reserved IP addresses inside of your DHCP scope, these do not get allocated except to the devices using the reserved addresses.

For routers and access points, we use Static IP addresses outside the DHCP scope entirely.

For printers (which have a habit of changing) we use Reserved IP addresses.
Lee W, MVPTechnology and Business Process Advisor
Most Valuable Expert 2013

Commented:
DHCP has no control over the validity of IP Addresses.  It can only assign addresses you permit it to.  The exclusion range(s) won't be served.
Distinguished Expert 2017

Commented:
DHCP is solely a service to distribute IPs. So if you create an exclusion rule, the IPs that are part of the exclusion would not be distributed by the DHCP server.
It in no way prevents the IPs from being utilized by statically configuring systems/devices to use an ip from the excluded range.
IT/EE Solution Guide
Commented:
DHCP reservations and exclusions are both intended to allow machines in a DHCP environment to maintain consistent addresses, but from the DHCP server's perspective, there are significant differences between the two:

    A reservation maps a media access control (MAC) address to an IP address. MAC addresses are typically hard-coded into network adapters, so that anytime a machine with a reserved MAC address requests a lease from the DHCP server, it will always obtain the same IP address. A reservation should be used if a machine needs to obtain its address from DHCP, but this address must not change.
    An exclusion removes an IP address or range of IP addresses from the pool of addresses that are given out by the DHCP server. The server will not give out excluded addresses. Therefore, a reservation should be used if a machine has a static IP address that falls within the DHCP address pool. This will prevent another machine from leasing the same IP address.

The main point to remember when distinguishing between exclusions and reservations is that exclusions should be used for machines that have locally configured static IP addresses (non-DHCP addresses, in other words), while reservations should be used for machines that require their addresses to be managed on the DHCP server but remain constant.

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