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To have the systems update any changes you want to make....<br />
Say you want to change the default gw... (New router), then shortening the interval to 10 minutes..<br />
Waiting for the longest Lease time to expire..., then cutover the router and change GW in DHCP...<br />
Takes all systems to update within that 10 minute window....<br />
<br />
Also if a system leaves an your network (to never return) &nbsp;the address will be available after a while.<br />
(lease expires, unless you also expire all leases by hand.)
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To have the systems update any changes you want to make....
Say you want to change the default gw... (New router), then shortening the interval to 10 minutes..
Waiting for the longest Lease time to expire..., then cutover the router and change GW in DHCP...
Takes all systems to update within that 10 minute window....

Also if a system leaves an your network (to never return)  the address will be available after a while.
(lease expires, unless you also expire all leases by hand.)

Principal Support Engineer

DrDave242

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Correct, DHCP clients are required to report back to the server after about half the lease time, to get the current setup DHCP options, like default gateway, routing options etc.<br />
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But a reservation never expires, the lease time is not kept for them. That part of noci's answer is not correct.
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Correct, DHCP clients are required to report back to the server after about half the lease time, to get the current setup DHCP options, like default gateway, routing options etc.

But a reservation never expires, the lease time is not kept for them. That part of noci's answer is not correct.

Software Engineer

noci

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I have a 2012 r2 DHCP server . we are currently only using static reservations . &nbsp; Why do we need a lease time if the static reservation is permineat?
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I have a 2012 r2 DHCP server . we are currently only using static reservations .   Why do we need a lease time if the static reservation is permineat?

Static lease registration and lease time

The Dynamic Host Configuration Protocol (DHCP) is an auto configuration protocol used on IP networks and an extension of the Bootstrap Protocol. DHCP allows for computers to be configured automatically to communicate with each other over an IP network without the need for manual setup by a network administrator. The implementation of DHCP relies on a DHCP server to hand out network configuration information to DHCP-capable clients that request an IP address (and other information required or useful in communicating with other devices on an IP network). In addition to an IP address, common configuration information served over DHCP includes a default gateway, subnet mask and DNS sever(s).

DHCP

Networking is the process of connecting computing devices, peripherals and terminals together through a system that uses wiring, cabling or radio waves that enable their users to communicate, share information and interact over distances. Often associated are issues regarding operating systems, hardware and equipment, cloud and virtual networking, protocols, architecture, storage and management.