## **Objective**

Provide **DHCP (IPv4 and IPv6)** for client networks in HQ1, HQ2, and the branches, including **DHCP relay (ip helper-address)**, so that:

- clients in VLAN 101 and 102 automatically receive IP addresses
- each site uses the **virtual gateway (.10)**
- DHCP runs centrally on defined devices
- remote networks can reach DHCP via relay
- IPv6 address assignment in HQ2 is provided for VLAN 102

---

## **1. DHCP Design**

- DHCP servers:
    - HQ1 → DS1
    - HQ2 → DS3
    - Branches → BR1 / BR2
- DHCP for: VLAN 101 & 102
- Gateway: always **.10** (HSRP VIP)
- Address range: .101 – .254
- DHCP relay: everywhere the DHCP server is **not local** to the VLAN
- IPv6 DHCP: HQ2 only, VLAN 102

---

## **2. DHCP on Distribution Switches (HQ)**

### **2.1 DS1 – DHCP Server HQ1**

```
ip dhcp excluded-address 10.10.101.1 10.10.101.100
ip dhcp excluded-address 10.10.102.1 10.10.102.100

ip dhcp pool HQ1_VLAN101
 network 10.10.101.0 255.255.255.0
 default-router 10.10.101.10
```

---

## **3. DHCP Relay (ip helper-address)**

DHCP relay is configured on all **SVIs or subinterfaces** where clients exist **if the DHCP server is not local** to that VLAN.

---

### **3.1 HQ1 – DHCP Relay on DS2**

```
interface Vlan101
 ip helper-address 10.10.100.11
```

(DS1 is the DHCP server, so no relay is required there.)

---

## **4. DHCP in the Branches**

### **4.1 BR1 – DHCP VLAN 101 (Local)**

```
ip dhcp excluded-address 10.1.101.1 10.1.101.100

ip dhcp pool BR1_VLAN101
 network 10.1.101.0 255.255.255.0
 default-router 10.1.101.10
```

No DHCP relay required (local DHCP server).

---

## **5. DHCPv6 in HQ2 (VLAN 102)**

### **5.1 DHCPv6 Pool (DS3)**

```
ipv6 dhcp pool HQ2_VLAN102_V6
 address prefix 2001:DB8:0:102::/64
```

### **5.2 VLAN 102 Interface**

```
interface Vlan102
 ipv6 dhcp server HQ2_VLAN102_V6
 ipv6 nd managed-config-flag
```

---

## **6. Verification**

```
show ip dhcp binding
show ip dhcp pool
show ipv6 dhcp binding
```

Expected:

- HQ1/HQ2 clients receive IPv4 addresses even with centralized DHCP
- ip helper-address configured correctly
- branch clients receive addresses from the local router
- HQ2 VLAN 102 IPv6 clients receive addresses