NetOps Toolkit

Cisco IOS

DHCP Pool Generator

Generate Cisco DHCP server pool configurations

What is DHCP?

Dynamic Host Configuration Protocol (DHCP) automatically hands out IP addresses and options (gateway, DNS, lease) to clients so you do not configure every device by hand.

  • Each DHCP pool usually maps to a single VLAN or IP subnet.
  • Always exclude static addresses for gateways, servers and printers.
  • On Cisco routers, the default gateway is configured as default-router inside the pool.

Basic DHCP Message Flow

StepMessageDirection
1DHCPDISCOVERClient → broadcast, looking for any server
2DHCPOFFERServer → client, offers an IP and options
3DHCPREQUESTClient → server, requests that specific offer
4DHCPACKServer → client, confirms lease and options

DHCP Design Tips

  • Use DHCP snooping on access switches; mark uplinks as trusted.
  • Keep scopes sized for your actual user count plus growth.
  • Document reservations and critical devices that must not change IP.