H3C DHCP User manual

DHCP Quick Start Configuration Guide

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i

Contents

Configuring dynamic IPv4 address assignment ·············································1

Introduction ························································································································································1

Network configuration ········································································································································1

Procedure···························································································································································1

Verifying the configuration··································································································································3

Configuration files ··············································································································································3

Related documentation······································································································································4

Configuring DHCP relay agent·······································································5

Introduction ························································································································································5

Network configuration ········································································································································5

Procedure···························································································································································5

Verifying the configuration··································································································································7

Configuration files ··············································································································································7

Related documentation······································································································································8

Configuring DHCP snooping··········································································9

Introduction ························································································································································9

Network configuration ········································································································································9

Procedure···························································································································································9

Verifying the configuration································································································································10

Configuration files ············································································································································10

Related documentation····································································································································10

Configuring dynamic IPv6 address assignment ···········································11

Introduction ······················································································································································11

Network configuration ······································································································································11

Procedure·························································································································································11

Verifying the configuration································································································································13

Configuration files ············································································································································14

Related documentation····································································································································15

1

Configuring dynamic IPv4 address

assignment

Introduction

The following example describes the basic procedure to configure an interface as a DHCP server for

dynamic IPv4 address assignment.

Network configuration

As shown in Figure 1, the core switch has three VLANs. Host A, Host B, and Host C are in VLAN 5,

VLAN 6, and VLAN 7, respectively. Configure the core switch as a DHCP server to meet the following

requirements:

•

The clients on subnets 192.168.5.0/24, 192.168.6.0/24, and 192.168.7.0/24 can obtain IP

addresses through DHCP.

•

The IP addresses of VLAN-interface 5, VLAN-interface 6, and VLAN-interface 7 on the switch

are 192.168.5.254/24, 192.168.6.254/24, and 192.168.7.254/24, respectively.

•

For the hosts in subnet 192.168.5.0/24, the DNS server IP address is 192.168.5.100 and the

gateway IP address is 192.168.5.254/24.

•

For the hosts in subnet 192.168.6.0/24, the DNS server IP address is 192.168.6.100 and the

gateway IP address is 192.168.6.254/24.

•

For the hosts in subnet 192.168.7.0/24, the DNS server IP address is 192.168.7.100 and the

gateway IP address is 192.168.7.254/24.

Figure 1 Network diagram

Procedure

# Enable DHCP on the switch.

<Switch> system-view

[Switch] dhcp enable

Switch

GE1/0/5

VLAN 5

Host A VLAN 6

Host B VLAN 7

Host C

GE1/0/7

GE1/0/6

2

# Assign GigabitEthernet 1/0/5, GigabitEthernet 1/0/6, GigabitEthernet 1/0/7 to VLAN 5, VLAN 6,

and VLAN 7, respectively.

[Switch] vlan 5

[Switch-vlan5] port gigabitEthernet 1/0/5

[Switch-vlan5] quit

[Switch]vlan 6

[Switch-vlan6] port gigabitEthernet 1/0/6

[Switch-vlan6] quit

[Switch]vlan 7

[Switch-vlan7] port gigabitEthernet 1/0/7

[Switch-vlan7] quit

# Assign IP addresses to VLAN-interface 5, VLAN-interface 6, and VLAN-interface 7. Each VLAN

interface acts as the gateway in the VLAN to which the interface belongs.

[Switch] interface vlan-interface 5

[Switch-Vlan-interface5] ip address 192.168.5.254 255.255.255.0

[Switch-Vlan-interface5] quit

[Switch]interface vlan-interface 6

[Switch-Vlan-interface6] ip address 192.168.6.254 255.255.255.0

[Switch-Vlan-interface6] quit

[Switch]interface vlan-interface 7

[Switch-Vlan-interface7] ip address 192.168.7.254 255.255.255.0

[Switch-Vlan-interface7] quit

# (Optional.) Exclude specific IP addresses (such as DNS server IP addresses) from dynamic IP

address assignment.

[Switch] dhcp server forbidden-ip 192.168.5.100

[Switch] dhcp server forbidden-ip 192.168.6.100

[Switch] dhcp server forbidden-ip 192.168.7.100

# Create IP address pool 5 to assign IP addresses to the clients on subnet 192.168.5.0/24.

[Switch] dhcp server ip-pool 5

[Switch-dhcp-pool-5] network 192.168.5.0 mask 255.255.255.0

[Switch-dhcp-pool-5] dns-list 192.168.5.100

[Switch-dhcp-pool-5] gateway-list 192.168.5.254

[Switch-dhcp-pool-5] quit

# Create IP address pool 6 to assign IP addresses to the clients on subnet 192.168.6.0/24.

[Switch] dhcp server ip-pool 6

[Switch-dhcp-pool-6] network 192.168.6.0 mask 255.255.255.0

[Switch-dhcp-pool-6] dns-list 192.168.6.100

[Switch-dhcp-pool-6] gateway-list 192.168.6.254

[Switch-dhcp-pool-6] quit

# Create IP address pool 7 to assign IP addresses to the clients on subnet 192.168.7.0/24.

[Switch] dhcp server ip-pool 7

[Switch-dhcp-pool-7] network 192.168.7.0 mask 255.255.255.0

[Switch-dhcp-pool-7] dns-list 192.168.7.100

[Switch-dhcp-pool-7] gateway-list 192.168.7.254

[Switch-dhcp-pool-7] quit

3

Verifying the configuration

# Check the IP addresses and other network settings of Host A, Host B, and Host C. Use the

display dhcp server ip-in-use command to view the IP addresses assigned by the DHCP

server.

[Switch] display dhcp server ip-in-use

IP address Client-identifier/ Lease expiration Type

Hardware address

192.168.5.1 0031-3865-392e-6262-Jan 14 22:25:03 2021 Auto(C)

3363-2e30-3230-352d-

4745-302f-30

192.168.6.2 0031-fe65-4203-7e02-Jan 14 22:25:03 2021 Auto(C)

3063-5b30-3230-4702-

620e-712f-5e

192.168.7.3 3030-3030-2e30-3030-Jan 9 10:45:11 2021 Auto(C)

662e-3030-3033-2d45-

7568-6572-1e

The output shows that the DHCP server can assign IP addresses and other network settings to the

clients on subnets 192.168.5.0/24, 192.168.6.0/24, and 192.168.7.0/24 correctly.

Configuration files

•

Switch:

#

dhcp enable

dhcp server forbidden-ip 192.168.5.100

dhcp server forbidden-ip 192.168.6.100

dhcp server forbidden-ip 192.168.7.100

#

vlan 5 to 7

#

dhcp server ip-pool 5

gateway-list 192.168.5.254

network 192.168.5.0 mask 255.255.255.0

dns-list 192.168.5.100

#

dhcp server ip-pool 6

gateway-list 192.168.6.254

network 192.168.6.0 mask 255.255.255.0

dns-list 192.168.6.100

#

dhcp server ip-pool 7

gateway-list 192.168.7.254

network 192.168.7.0 mask 255.255.255.0

dns-list 192.168.7.100

#

interface Vlan-interface5

4

ip address 192.168.5.254 255.255.255.0

#

interface Vlan-interface6

ip address 192.168.6.254 255.255.255.0

#

interface Vlan-interface7

ip address 192.168.7.254 255.255.255.0

#

interface GigabitEthernet1/0/5

port link-mode bridge

port access vlan 5

#

interface GigabitEthernet1/0/6

port link-mode bridge

port access vlan 6

#

interface GigabitEthernet1/0/7

port link-mode bridge

port access vlan 7

#

Related documentation

•

DHCP configuration in the Layer 3 IP services configuration guide for the device.

•

DHCP commands in the Layer 3 IP services command reference for the device.

5

Configuring DHCP relay agent

Introduction

The following example describes the basic procedure to configure an interface as a DHCP relay

agent. The DHCP relay agent enables clients to obtain IP addresses and configuration parameters

from a DHCP server on another subnet.

Network configuration

As shown in Figure 2, Switch Aacts as the core switch and has two VLANs. Host Aand Host B are in

VLAN 5 and VLAN 6, respectively. The DHCP server and the hosts run on different subnets and

Switch A is the gateway for these hosts. Configure the network to meet the following requirements:

•

The DHCP clients run on subnets 192.168.5.0/24 and 192.168.6.0/24, and the DHCP server IP

address is 192.168.7.100/24.

•

Switch A acts as the DHCP relay agent for clients, so these clients can obtain IP addresses in

subnets 192.168.5.0/24 and 192.168.6.0/24, and other network settings from the DHCP server.

Figure 2 Network diagram

Procedure

1. Configure Switch B.

# Create VLAN 5 and VLAN 6, and then assign GigabitEthernet 1/0/2 and GigabitEthernet 1/0/3

to VLAN 5 and VLAN 6, respectively.

<SwitchB> system-view

[SwitchB] vlan 5

[SwitchB-vlan5] port gigabitEthernet 1/0/2

[SwitchB-vlan5] quit

[SwitchB] vlan 6

GE1/0/1

Switch B

GE1/0/2 GE1/0/3

DHCP server

Switch A

GE1/0/1

GE1/0/2

VLAN 5

Host A VLAN 6

Host B

6

[SwitchB-vlan6] port gigabitEthernet 1/0/3

[SwitchB-vlan6] quit

# Configure GigabitEthernet 1/0/1 as a trunk port, and allow packets from all VLANs to pass

through the trunk port.

[SwitchB] interface gigabitEthernet 1/0/1

[SwitchB-GigabitEthernet1/0/1] port link-type trunk

[SwitchB-GigabitEthernet1/0/1] port trunk permit vlan all

[SwitchB-GigabitEthernet1/0/1] quit

2. Configure Switch A.

# Enable DHCP.

<SwitchA> system-view

[SwitchA] dhcp enable

# Create VLAN 5, VLAN 6, and VLAN 7, and then assign GigabitEthernet 1/0/2 to VLAN 7.

[SwitchA] vlan 5 to 7

[SwitchA] interface GigabitEthernet 1/0/2

[SwitchA-GigabitEthernet1/0/2] port access vlan 7

[SwitchA-GigabitEthernet1/0/2] quit

# Configure GigabitEthernet 1/0/1 as a trunk port, and allow packets from all VLANs to pass

through the trunk port.

[SwitchA] interface gigabitEthernet 1/0/1

[SwitchA-GigabitEthernet1/0/1] port link-type trunk

[SwitchA-GigabitEthernet1/0/1] port trunk permit vlan all

[SwitchA-GigabitEthernet1/0/1] quit

# Assign an IP address to VLAN 5, VLAN 6, and VLAN 7, respectively.

[SwitchA] interface vlan-interface 5

[SwitchA-Vlan-interface5] ip address 192.168.5.1 255.255.255.0

[SwitchA-Vlan-interface5] quit

[SwitchA] interface vlan-interface 6

[SwitchA-Vlan-interface6] ip address 192.168.6.1 255.255.255.0

[SwitchA-Vlan-interface6] quit

[SwitchA]interface vlan-interface 7

[SwitchA-Vlan-interface7] ip address 192.168.7.1 255.255.255.0

[SwitchA-Vlan-interface7] quit

# Enable the DHCP relay agent mode on VLAN-interface 5.

[SwitchA] interface vlan-interface 5

[SwitchA-Vlan-interface5] dhcp select relay

# Assign IP address 192.168.7.100 to the DHCP server.

[SwitchA-Vlan-interface5] dhcp relay server-address 192.168.7.100

# Enable the DHCP relay agent mode on VLAN-interface 6.

[SwitchA] interface vlan-interface 6

[SwitchA-Vlan-interface6] dhcp select relay

# Assign IP address 192.168.7.100 to the DHCP server.

[SwitchA-Vlan-interface6] dhcp relay server-address 192.168.7.100

3. Configure DHCP server. Details are not shown.

# Assign IP address 192.168.7.100/24 to the NIC of the DHCP server.

# Configure IP address 192.168.7.1 as the gateway for the DHCP server.

# Make sure the DHCP server can ping 192.168.5.1 and 192.168.6.1.

7

Verifying the configuration

Check whether Host A and Host B can obtain IP addresses and other network settings from the

DHCP server.

Configuration files

•

Switch B:

#

vlan 5 to 6

#

interface GigabitEthernet1/0/1

port link-mode bridge

port link-type trunk

port trunk permit vlan all

#

interface GigabitEthernet1/0/2

port link-mode bridge

port access vlan 5

#

interface GigabitEthernet1/0/3

port link-mode bridge

port access vlan 6

•

Switch A:

#

dhcp enable

#

vlan 5 to 7

#

interface Vlan-interface5

ip address 192.168.5.1 255.255.255.0

dhcp select relay

dhcp relay server-address 192.168.7.100

#

interface Vlan-interface6

ip address 192.168.6.1 255.255.255.0

dhcp select relay

dhcp relay server-address 192.168.7.100

#

interface Vlan-interface7

ip address 192.168.7.1 255.255.255.0

#

interface Ten-GigabitEthernet1/0/1

port link-mode bridge

port link-type trunk

port trunk permit vlan all

#

8

interface Ten-GigabitEthernet1/0/2

port link-mode bridge

port access vlan 7

#

H3C DHCP User manual

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