The Cisco Catalyst 3750 switch is a powerful networking device that can function as a DHCP server when a dedicated DHCP server is not available. This feature allows the switch to dynamically allocate IP addresses to network devices. However, for optimal performance, it is recommended to eventually migrate DHCP services to a dedicated server to preserve the switch’s memory and CPU resources.
In this guide, we will walk through the process of configuring a DHCP server on a Cisco 3750 switch. We will first establish a serial connection with the switch, enable DHCP, and configure a DHCP pool with a specified range of IP addresses.
Step 1: Connect to the Cisco 3750 Switch
To start, you need to establish a serial command line connection between your computer and the Cisco 3750 switch.
Requirements:
-
A Cisco serial console cable (nine-pin connector)
-
A Windows computer with a serial COM port
-
A terminal emulation program such as PuTTY or Tera Term
Connection Process:
-
Attach the Cisco serial console cable’s nine-pin connector to the COM port on your Windows computer.
-
Plug the other end of the cable into the “Console” port of the Cisco 3750 switch.
-
Open your terminal emulation software and set the following serial communication parameters:
-
Baud rate: 9600
-
Data bits: 8
-
Parity: None
-
Stop bits: 1
-
Flow control: None
-
-
Press Enter twice to wake up the console.
Step 2: Enter Privileged EXEC Mode
Once connected to the switch, follow these steps to gain access to configuration mode:
-
Type
enableand press Enter. -
If prompted, enter the Enable password and press Enter.
Step 3: Enter Global Configuration Mode
-
Type
config tand press Enter.
Step 4: Configure a Network Interface
To configure an interface with a static IP address:
-
Type
interface fastethernet 0/1and press Enter. -
Enter
no switchportto disable Layer 2 switching on the interface. -
Assign an IP address to the interface by typing:
ip address 10.0.0.1 255.0.0.0 -
Exit the interface configuration mode by typing
exit
Step 5: Configure the DHCP Pool
To create and configure a DHCP pool:
-
Type
ip dhcp pool pool-name(replace "pool-name" with your desired name) and press Enter. -
Define the network and subnet mask using:
network 10.0.0.0 255.0.0.0 -
Specify the default gateway for the network:
default-router 10.0.0.1 -
Define the DNS server IP address:
dns-server 10.0.0.100 -
Exit DHCP configuration mode by typing
exittwice.
Step 6: Save the Configuration
To ensure the settings persist after a reboot:
-
Type
wrand press Enter to save the configuration.
You have successfully configured DHCP on your Cisco Catalyst 3750 switch 🙂 This setup enables dynamic IP address assignment to network clients, ensuring efficient IP management. While this works as a temporary solution, consider migrating DHCP services to a dedicated server for better performance and scalability.
If you have any questions, let me know in the comments 😉
very informative 🙂