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BeginnerPublished 2026-07-02

DHCP Exclusions: Reserved Statics on a Single LAN

Bundle lab

Configure an IOS-XE router as a DHCP server with a correctly scoped pool and an excluded-address range that protects the gateway and a reserved static server (.10). Two Alpine clients obtain addresses dynamically from the remaining range (starting at .11). Verify leases, confirm the excluded count, and ensure the reserved static never appears as a DHCP binding.

Track
Est. time
35 minutes
Difficulty
Beginner
Topics

Learning objectives

  • Build a DHCP pool on an IOS-XE router with required options: network/mask, default-router, dns-server, domain-name, and lease.
  • Implement an excluded-address range that reserves infrastructure and static server IPs from leasing.
  • Operate Alpine Linux clients as DHCP clients (udhcpc) and verify they lease addresses within the allowed range.
  • Validate router DHCP state with show commands: pool utilization, excluded count, and current bindings.
  • Confirm end-to-end reachability from dynamic clients to both the gateway and a statically addressed server.

Troubleshooting focus

  • Client fails to get an address due to missing DHCP pool or wrong network mask.
  • Duplicate IP conflict caused by not excluding the reserved static server address.
  • Incorrect default-router option prevents client from reaching off-host destinations.
  • SW1 access port(s) down or mis-cabled so DISCOVER never reaches the router.
  • Client not actually running a DHCP client (udhcpc) or link down at boot.

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How this lab is graded
  • Build it your way. Where a lab lets you choose a value — a VLAN name, an interface description — grading checks that you configured it, not which name you picked. Names that another line has to reference, like an ACL applied with access-class, are stated in the guide and do have to match.
  • Addresses, modes and protocol keywords are exact. An IP address, a subnet mask, switchport mode trunk, an encapsulation — these carry the meaning of the lab, so they are graded as written in the guide.
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