Ten Steps for configuring DHCP ports

In the settings of the DHCP service, routes and switches have always been the focus of attention. In its settings, Do you know some port problems? Configure the network environment of the DHCP server instance for a Cisco 3750 switch: A 3750 switch is divided into three VLANs. vlan2 is the network where the server is located, and the IP address segment is 192.168.2.0. The subnet mask is 255.255.255.0, gateway: 192.168.2.1. The Domain server is windows 2003 advance server and serves as a DNS server. The IP address is 192.168.2.10, vlan3 is the network where client 1 is located, the IP address segment is 192.168.3.0, And the subnet mask is 255.255.255.0, gateway: 192.168.3.1 is named work01, vlan4 is the network where client 2 is located, named work02, IP address segment is 192.168.4.0, subnet mask: 255.255.255.0, Gateway: 192.168.4.1, 3750 as DHCP server, ports 1-8 are divided into VLAN 2, ports 9-16 are divided into VLAN 3, and ports 17-24 are divided into VLAN 4.

DHCP server implementation functions:
Each VLAN retains 2-10 IP addresses regardless of configuration. For example, the IP address range of 192.168.2.0 is retained, and the IP address ranges from 192.168.2.2 to 192.168.2.10 are retained.
The address segment is not allocated.

Security requirements:
VLAN 3 and VLAN 4 are not allowed to access each other, but both can access the VLAN 2 where the server is located,
The default access control list rule is to reject all packages.

The configuration command and steps are as follows:

Step 1: Create a VLAN:
Switch> en
Switch # Vlan Database
Switch (Vlan)> Vlan 2 Name server
Switch (Vlan)> Vlan 3 Name work01
Switch (vlan)> Vlan 4 Name work02

Step 2: Set the vlan ip Address:
Switch # Config T
Switch (Config)> Int Vlan 2
Switch (Config-vlan) Ip Address 192.168.2.1 255.255.255.0
Switch (Config-vlan) No Shut
Switch (Config-vlan)> Int Vlan 3
Switch (Config-vlan) Ip Address 192.168.3.1 255.255.255.0
Switch (Config-vlan) No Shut
Switch (Config-vlan)> Int Vlan 4
Switch (Config-vlan) Ip Address 192.168.4.1 255.255.255.0
Switch (Config-vlan) No Shut
Switch (Config-vlan) Exit
/* Note: Because the ports are not configured to VLAN2, 3, 4 at this time, each VLAN will be DOWN. After the ports are allocated to each VLAN, the VLAN will get up */

Step 3: Set port global Parameters
Switch (Config) Interface Range Fa 0/1-24
Switch (Config-if-range) Switchport Mode Access
Switch (Config-if-range) Spanning-tree Portfast

Step 4: add the port to VLAN2, 3, 4
/* Add Port 1-8 to VLAN 2 */
Switch (Config) Interface Range Fa 0/1-8
Switch (Config-if-range) Switchport Access Vlan 2

/* Add Port 9-16 to VLAN 3 */
Switch (Config) Interface Range Fa 0/9-16
Switch (Config-if-range) Switchport Access Vlan 3

/* Add Port 17-24 to VLAN 4 */
Switch (Config) Interface Range Fa 0/17-24
Switch (Config-if-range) Switchport Access Vlan 4
Switch (Config-if-range) Exit

/* After this step, each VLAN will get up */

Step 5: Configure 3750 as the DHCP server
/* Configure available address pools and corresponding parameters for VLAN 2. You need to set several address pools for several VLANs */
Switch (Config) Ip Dhcp Pool Test01
/* Set the allocable subnet */
Switch (Config-pool) Network 192.168.2.0 255.255.255.0
/* Set the DNS server */
Switch (Config-pool) Dns-server 192.168.2.10
/* Set the gateway for this subnet */
Switch (Config-pool) Default-router 192.168.2.1

/* Configure the address pool used by VLAN 3 and corresponding parameters */
Switch (Config) Ip Dhcp Pool Test02
Switch (Config-pool) Network 192.168.3.0 255.255.255.0
Switch (Config-pool) Dns-server 192.168.2.10
Switch (Config-pool) Default-router 192.168.3.1

/* Configure the address pool and corresponding parameters used by VLAN 4 */
Switch (Config) Ip Dhcp Pool Test03
Switch (Config-pool) Network 192.168.4.0 255.255.255.0
Switch (Config-pool) Dns-server 192.168.2.10
Switch (Config-pool) Default-router 192.168.4.1

Step 6: Set DHCP to retain unassigned addresses
Switch (Config) Ip Dhcp Excluded-address 192.168.2.2 192.168.2.10
Switch (Config) Ip Dhcp Excluded-address 192.168.3.2 192.168.3.10
Switch (Config) Ip Dhcp Excluded-address 192.168.4.2 192.168.4.10

Step 7: Enable Routing
/* After a route is enabled, each VLAN host can access each other */
Switch (Config) Ip Routing

Step 8: configure the access control list
Switch (Config) access-list 103 permit ip 192.168.2.0 0.0.255 192.168.3.0 0.0.255
Switch (Config) access-list 103 permit ip 192.168.3.0 0.0.255 192.168.2.0 0.0.255
Switch (Config) access-list 103 permit udp any eq bootpc
Switch (Config) access-list 103 permit udp any eq tftp
Switch (Config) access-list 103 permit udp any eq bootpc any
Switch (Config) access-list 103 permit udp any eq tftp any
Switch (Config) access-list 104 permit ip 192.168.2.0 0.0.255 192.168.4.0 0.0.255
Switch (Config) access-list 104 permit ip 192.168.4.0 0.0.255 192.168.2.0 0.0.255
Switch (Config) access-list 104 permit udp any eq tftp any
Switch (Config) access-list 104 permit udp any eq bootpc any
Switch (Config) access-list 104 permit udp any eq bootpc any
Switch (Config) access-list 104 permit udp any eq tftp any

Step 9: Application access control list
/* Apply the access control list to VLAN 3 and VLAN 4. VLAN 2 is not required */
Switch (Config) Int Vlan 3
Switch (Config-vlan) ip access-group 103 out
Switch (Config-vlan) Int Vlan 4
Switch (Config-vlan) ip access-group 104 out

Step 10: end and save the configuration
Switch (Config-vlan) End
Switch # write memory