IP Configuration Overview

Overview

This lecture explains how to configure IP addresses on devices, covering static addresses, DHCP, APIPA, and best practices.

Basic IP Configuration Parameters

• Every device requires a unique IP address for network communication.
• A subnet mask determines which subnet the device belongs to (e.g., 255.255.255.0).
• The combination of an IP address and subnet mask defines an IP subnet.
• The default gateway is the router's IP that allows communication outside the local subnet (e.g., 192.168.1.1).
• DNS server and other parameters may also need manual configuration.

Static vs. Dynamic IP Addressing

• Static IP addresses are manually assigned and do not change.
• Static configuration requires inputting the IP address, subnet mask, gateway, and DNS manually on the device.
• Manually managing static IPs is time-consuming and not scalable for large networks.
• DHCP (Dynamic Host Configuration Protocol) automates IP address assignment for devices.

DHCP Reservations

• DHCP reservations assign a specific IP to a device based on its MAC address.
• IP reservations are managed centrally on the DHCP server, not individually on each device.
• Updating network settings (like DNS or gateway) is easier with DHCP reservations as changes are made on the server.

APIPA (Automatic Private IP Addressing)

• If a device cannot reach a DHCP server, it assigns itself an APIPA (link-local) address.
• APIPA addresses range from 169.254.1.0 to 169.254.254.255.
• Devices with APIPA addresses can communicate only within the local subnet, not externally.
• The device uses ARP requests to ensure its APIPA address is unique on the network.

Key Terms & Definitions

• IP Address — Unique identifier for a device on a network.
• Subnet Mask — Used to delineate the subnet of an IP address.
• Default Gateway — Router IP address that connects a subnet to external networks.
• DNS Server — Resolves domain names to IP addresses.
• Static IP Address — An IP address manually set and fixed for a device.
• DHCP (Dynamic Host Configuration Protocol) — Protocol that automatically assigns IP addresses to devices.
• DHCP Reservation — A permanent IP assignment to a device via DHCP by MAC address.
• APIPA (Automatic Private IP Addressing) — Self-assigned local IP when DHCP is unavailable.
• ARP (Address Resolution Protocol) — Network protocol used to check if an IP is already in use.

Action Items / Next Steps

• Double-check all manual IP configuration entries for accuracy.
• Consult network administrator for correct subnet mask and gateway.
• Troubleshoot DHCP connectivity if device receives an APIPA address.