ip dhcp pool [name]
Creates a logical DHCP scope address pool and shifts the CLI into DHCP Configuration Mode. This allows the router to act as a centralized DHCP server, dynamically leasing IPv4 architecture arrangements directly to local clients.
Quick Reference
Router(config)#Router(config-dhcp)#no ip dhcp pool [name]Scope Parameters & Options
Once you enter the Router(config-dhcp)# submode, you must configure the metrics that the server will hand out to endpoints during the standard DORA negotiation cycle.
| Command Substring | Operational Metric Defined |
|---|---|
| network [id] [mask] | Defines the overall block boundary of IPs available for lease. Uses traditional dotted-decimal netmasks. |
| default-router [ip] | Defines the default gateway address sent to endpoints (typically the router's local interface IP address). |
| dns-server [ip1] [ip2] | Provides primary and secondary DNS resolution addresses to clients (e.g., 8.8.8.8). |
| lease [days hours mins] | Sets how long an endpoint holds an address assignment before needing to request a renewal. Default is 1 day. |
CLI Deployment Scenarios
Scenario 1: Setting up a Complete Scope Block
Provisioning an IP assignment matrix for an engineering office network on the 10.20.30.0/24 subnet segment.
CCNA Exam Gotchas
The IP Conflict Overlap Trap
If you configure an ip dhcp pool and declare a network, the router immediately prepares to distribute every address in that block. If your router gateway is sitting at 10.20.30.1 and you fail to configure an exclusion block, the server will eventually hand 10.20.30.1 to a workstation, creating a massive IP duplicate conflict that takes down the local gateway vector.
Crucial Order: Always execute the ip dhcp excluded-address command globally before finalizing your pool metrics.
Implicit Verification Processing
How does a router know which physical interface should listen to which logical pool? It parses the networks. If an incoming DHCP discover frame hits interface GigabitEthernet0/0, the router checks the interface's IP (e.g., 10.20.30.1). It then matches it against the pool with the corresponding network 10.20.30.0 declaration. If no interfaces match the pool statement network range, the router will completely ignore client inquiries.