lease [days] [hours] [mins]
Sets the DHCP lease duration for addresses assigned from a DHCP pool, controlling how long a client can use an IP address before renewing.
lease [days] [hours] [mins]When to Use This Command
- Configure a short lease (e.g., 1 hour) for a guest Wi-Fi network to quickly reclaim unused addresses.
- Set a long lease (e.g., 7 days) for a corporate wired network to reduce DHCP renewal traffic.
- Use default lease (1 day) for a general-purpose LAN where devices are relatively stable.
- Set lease to 0 days 0 hours 0 minutes for infinite lease (not recommended, but used for static-like assignments).
Command Examples
Setting a 2-day lease
lease 2 0 0This command sets the lease duration to 2 days, 0 hours, 0 minutes. No output is displayed upon successful configuration.
Setting a 12-hour lease
lease 0 12 0This sets the lease to 12 hours. Useful for environments where devices connect temporarily.
Understanding the Output
The lease command does not produce any output when executed. To verify the configured lease time, use 'show ip dhcp pool [pool-name]' or 'show running-config | section ip dhcp pool'. In the output of 'show ip dhcp pool', look for the 'Lease time' field which displays the configured duration (e.g., 'Lease time (days/hours/minutes): 2/0/0'). A lease of 0/0/0 indicates infinite lease. Ensure the lease time matches your network policy; too short may cause excessive renewal traffic, too long may waste IPs if devices leave.
CCNA Exam Tips
CCNA exam may test that lease command is configured in DHCP pool configuration mode, not global config.
Remember that default lease time is 1 day if not explicitly configured.
Infinite lease (0 0 0) is possible but rarely used; exam might ask about its effect on address exhaustion.
Lease time affects DHCP renewal and rebinding timers (50% and 87.5% of lease).
Common Mistakes
Mistake: Configuring lease under global config mode instead of DHCP pool config mode. Consequence: command rejected.
Mistake: Forgetting to set lease and relying on default; may not suit network requirements.
Mistake: Setting lease to 0 0 0 (infinite) without understanding it prevents address reclamation.
Related Commands
ip dhcp pool [name]
Creates a DHCP pool and enters DHCP pool configuration mode, where you define the subnet, default gateway, DNS servers, and other DHCP options for assigning IP addresses to clients.
show ip dhcp pool
Displays the configuration and utilization statistics of a DHCP pool, used to verify pool settings and address allocation status.
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