In modern networking environments, IP addresses are often assigned dynamically using DHCP (Dynamic Host Configuration Protocol), which provides devices with temporary IP addresses known as leased IP addresses. The DHCP lease specifies how long the device can use the IP address before it needs to be renewed or reassigned. However, there are cases where administrators may need to change the assignment of a leased IP address due to network restructuring, conflicts, or administrative policies.
There are several reasons why you might need to change the assignment of a leased IP address:
When reorganizing your network or adjusting subnets, some devices may need to be moved to new IP ranges.
If two devices are inadvertently assigned the same IP address, manual intervention is needed to resolve the conflict.
Some networks may require specific devices, such as servers or printers, to have predictable IP addresses.
Assigning fixed IP addresses to critical devices can enhance network security and manageability.
Changing the assignment of a leased IP address involves adjusting the DHCP lease settings and possibly assigning static or reserved IPs.
Before changing the assignment of a leased IP address, it’s essential to understand how DHCP leases work.
When a device connects to a network, the DHCP server assigns it an IP address for a specific period, known as the lease time. Once the lease expires, the device must request a renewal to continue using the same IP address.
DHCP typically assigns dynamic IP addresses, meaning the address can change when the lease expires. However, network administrators can assign static or reserved IP addresses to ensure certain devices always receive the same IP.
Changing the lease assignment means either adjusting the lease time, releasing the current IP address, or setting a static IP for devices that require a permanent address.
Here’s how to modify the assignment of leased IP addresses on popular networking platforms.
Keenetic routers allow users to change the lease time for IP addresses through their web interface. This can help manage network performance and ensure devices receive IP addresses for appropriate durations.
| Setting | Default Value | Recommended for Heavy Networks |
| Lease Time | 86400 seconds (24 hours) | 3600 seconds (1 hour) for frequent IP changes |
| Static IP Reservation | Disabled | Enabled for critical devices |
In enterprise networks, IP Address Management (IPAM) tools provide centralized control over IP addressing. For example, tools like Infoblox or built-in IPAM systems in operating environments (such as Microsoft’s DHCP server) allow you to manage DHCP leases more efficiently.
If your network runs on Windows Server, you can adjust the lease time through the DHCP management console.
| Lease Time Setting | Windows Default | Recommended for Static Devices |
| Default Lease Time | 8 days | Set static lease for servers and printers |
| Approach | Best For | Key Advantages | Potential Drawbacks |
| Dynamic Lease Assignment | General-purpose networks, guest devices | Automatically assigns IPs | May lead to IP conflicts |
| Static IP Assignment | Servers, printers, critical devices | Ensures predictable IPs | Requires manual configuration |
| Reduced Lease Time | High-traffic networks, guest Wi-Fi | Frees up IP addresses quickly | Frequent renewals may burden the network |
Always assign static IP addresses to essential devices such as servers, printers, or network infrastructure to ensure they maintain consistent connectivity.
Reduce DHCP lease times for networks with frequent connections (e.g., guest Wi-Fi networks) to avoid IP exhaustion.
Use IPAM tools to monitor and resolve any IP address conflicts that may arise after adjusting leases.
Always test changes to IP leases on a small subset of devices before deploying them network-wide to ensure the changes work as expected without causing connectivity issues.
Changing the assignment of a leased IP address in a network is a straightforward process that can help administrators better manage network resources, prevent conflicts, and ensure critical devices have consistent connectivity. Whether adjusting lease times or assigning static IPs, proper management of DHCP leases improves network performance and simplifies administration.
Alexander Timokhin
COO
Alexander Timokhin
COO
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