IP Configuration of Core Switch Ports

To configure IP addresses on core switch ports, you typically assign the IP to a VLAN interface or convert a port to Layer 3, then set the IP and subnet mask via CLI.

Step 1: Access the Switch

Connect to the switch using one of the following methods:

• Console cable with a terminal emulator (PuTTY, Tera Term)
• SSH if the switch already has an IP configured
• Web interface (optional for some managed switches)

Step 2: Enter Global Configuration Mode

From privileged EXEC mode:

Switch> enableSwitch# configure terminal

Step 3: Configure a VLAN Interface (Management IP)

Most switches use a VLAN interface for IP configuration:

Switch(config)# interface vlan 1Switch(config-if)# ip address 192.168.1.10 255.255.255.0Switch(config-if)# no shutdownSwitch(config-if)# exit

• Replace 192.168.1.10 and 255.255.255.0 with your desired IP and subnet mask
• VLAN 1 is default, but you can use another VLAN if preferred

Step 4: Set Default Gateway

To allow the switch to communicate outside its subnet:

Switch(config)# ip default-gateway 192.168.1.1

Replace 192.168.1.1 with your network's gateway

Step 5: Configure Layer 3 Ports (Optional for Routing)

If you need the switch port itself to have an IP (for routing or inter-VLAN communication):

Switch(config)# interface gigabitEthernet 0/1Switch(config-if)# no switchportSwitch(config-if)# ip address 192.168.2.1 255.255.255.0Switch(config-if)# no shutdownSwitch(config-if)# exit

• no switchport converts the port from Layer 2 to Layer 3
• Assign the IP and subnet mask as needed

Step 6: Verify Configuration

Check the IP assignment and interface status:

Switch# show ip interface briefSwitch# ping 192.168.1.1

• Ensure the interface is up and reachable

Step 7: Secure Remote Access (Optional)

Enable SSH for secure management:

Switch(config)# crypto key generate rsaSwitch(config)# line vty 0 15Switch(config-line)# transport input sshSwitch(config-line)# login localSwitch(config-line)# exit

• Generate RSA keys and configure VTY lines for SSH access

Notes

• Use static IPs for core switches to prevent connectivity issues, especially in stacked configurations
• For DHCP, the switch can automatically receive an IP, but static assignment is recommended for core infrastructure
• Always ensure the VLAN used for management is active and has at least one port in the VLAN By following these steps, you can configure IP addresses on core switch ports for management, routing, or inter-VLAN communication.