DHCP Configuration

Configure DHCP (Multi-Scope Lab)

In this step, you’ll configure DHCP like it’s done in a real corporate environment. You’ll create multiple scopes, define exclusions, set DHCP options, adjust lease times, and create reservations — all using the DHCP management console.

Important Azure Reality Check

In Azure, virtual machine NICs receive IP addresses from Azure — not from your Windows DHCP server. That means this DHCP server will not hand out leases to Azure VMs.

That’s expected. Success in this lab is based on correct server-side configuration, not client lease testing.

After this page, you should be able to:

  • Create multiple DHCP scopes for different networks
  • Configure exclusions within a scope to protect infrastructure IPs
  • Set essential DHCP options (gateway, DNS)
  • Understand and adjust lease duration
  • Create DHCP reservations and explain when to use them
  • Validate DHCP configuration server-side

Lab Network Design (Pretend Corporate Environment)

Users LAN       : 192.168.1.0/24
Corporate Voice : 192.168.2.0/24
Guest Wi-Fi     : 192.168.3.0/24

DHCP Server     : dc1
Default Gateway : .254 in each subnet
DNS Server      : dc1

In a real network, routers or Layer 3 switches would relay DHCP requests from each subnet to this server.

Step 1: Open the DHCP Management Console

  1. Log into dc1
  2. Open Server Manager
  3. Click Tools → DHCP

Step 2: Create Scope – Users LAN

  1. Expand little arrow on the left -- Right-click IPv4 → New Scope
  2. Name: Users LAN
  3. Start IP: 192.168.1.10
  4. End IP: 192.168.1.200
  5. Subnet mask: 255.255.255.0
  6. Add exclusion: 192.168.1.10 – 192.168.1.20
    (reserved for printers, APs, or static devices. Normally with this subnet size, we would not need exclusions within the scope. We will still put these in for practice)
  7. Lease duration: 8 hours
  8. Activate the scope

This scope represents standard employee workstations. Infrastructure IPs live inside the same range but are protected using exclusions.

Step 3: Create Scope – Corporate Voice

  1. Create another scope under IPv4
  2. Name: Corporate Voice
  3. Start IP: 192.168.2.10
  4. End IP: 192.168.2.150
  5. Add exclusion: 192.168.2.10 – 192.168.2.30
    (voice gateways and call managers)
  6. Lease duration: 1 day
  7. Activate the scope

VOIP phones rely heavily on DHCP and often share subnets with statically addressed voice infrastructure.

Step 4: Create Scope – Guest Wi-Fi

  1. Create a third scope
  2. Name: Guest Wi-Fi
  3. Start IP: 192.168.3.50
  4. End IP: 192.168.3.250
  5. Add exclusion: 192.168.3.50 – 192.168.3.60
    (wireless controllers or captive portal appliances)
  6. Lease duration: 2 hours
  7. Activate the scope

Guest networks favor short leases and aggressive IP reuse.

Step 5: Configure DHCP Options (Per Scope)

For each scope:

  1. Click carrot to expand the scope -- Right-click Scope Options → Configure Options
  2. Set:
    • 003 Router: 192.168.X.254
      • (Note - "Router" is our default gateway in the lab scenario. We do not actually have a device with IP 192.168.x.254, however this is a very normal IP scheme that we might give to the last device on the edge of each branch. Usually this will be the firewall or VCE)
    • 006 DNS Servers: IP of dc1
    • 015 DNS Domain Name: lab.local
      • (We don't actually have a domain since we have not promoted a domain controller. We will still input lab.local for labbing purposes.) If you'd like to spin up a DC — see the Active Directory Basics lab.

Step 6: Create DHCP Reservations

  1. Right-click Reservations under a scope
  2. Select New Reservation
  3. Name: Printer-01
  4. IP Address: 192.168.1.15
  5. MAC Address: use any placeholder value

Reservations are preferred over manual static IPs because they remain centrally managed.

Step 7: Validate Configuration (Server-Side)

  • All scopes show Active
  • Exclusions fall inside the scope range
  • Options reflect correct gateway and DNS values
  • Reservations appear under the correct scope
  • DHCP service is running

Key Takeaways

  • Exclusions only matter if they are inside the scope’s address pool
  • Scopes represent subnets; exclusions protect shared infrastructure IPs
  • Lease duration should reflect device churn
  • Reservations offer consistency without manual static IPs
  • Correct configuration can be validated without clients