Learn computer networks, Wi-Fi, routers, IP addressing, network protocols, troubleshooting, and network security through practical guides and step-by-step explanations.
Networking Fundamentals · Beginner Guide
Every computer, phone, server, or other device communicating through an IP network needs a way to identify communication endpoints. IP addressing provides logical addresses that help network devices deliver data to the appropriate destinations.
In this guide, you will learn how IP addresses work, the difference between IPv4 and IPv6, public and private addressing, static and dynamic IPs, and several special IPv4 address ranges. You will also learn how to check your IP configuration on Windows.
IP stands for Internet Protocol. An IP address is a logical address associated with a network interface. IP packets carry source and destination addresses, allowing network systems to forward data toward its intended destination.
For example, your laptop might have a private IP address assigned by your home router. When it communicates with a website, packets travel through your local network and usually through a router before reaching the wider internet.
192.168.1.10
A possible private IPv4 address on a home network.
192.168.1.1
A common router address, though actual configurations vary.
Public IP
A globally routable address may be used to reach a public service.
These examples are illustrative. Real networks can use different private ranges, multiple interfaces, IPv6 addresses, proxies, and network address translation.
IPv4 uses a 32-bit address. It is commonly written as four decimal numbers separated by dots. Each number represents an 8-bit group called an octet and ranges from 0 to 255.
Example IPv4 address
Four octets × 8 bits = 32 bits. Each octet represents a binary value from 00000000 to 11111111, corresponding to decimal values from 0 to 255.
Each of the 32 bits can have a value of 0 or 1. Therefore, the total number of possible bit patterns is 2³², which equals 4,294,967,296.
Not all of these addresses are available for ordinary public host assignment. Some ranges are reserved for private networks, multicast, loopback, documentation, and other special purposes.
The address alone does not tell you the full network boundary. A prefix length or subnet mask identifies which bits belong to the network prefix. For example, 192.168.1.10/24 indicates a 24-bit prefix.
Learn subnet masks and CIDR notation →IP addresses and MAC addresses perform different jobs. An IP address is used by the Internet Protocol to identify packet endpoints. A MAC address is used by a link-layer technology for delivery on a local network segment.
| Feature | IP Address | MAC Address |
|---|---|---|
| Purpose | Logical network addressing | Local link-layer delivery |
| Common format | 192.168.1.10 | 00:1A:2B:3C:4D:5E |
| Can change? | Yes, depending on configuration | Hardware addresses may be overridden or randomized |
| Used by | Routers and IP systems | Local network interfaces and switches |
For example, when your laptop sends traffic to a remote website, the IP destination can remain the website's address as the packet travels across networks. The link-layer frame is rebuilt for each network hop, using the appropriate local link addresses.
Public and private IPv4 addresses serve different roles. Private IPv4 ranges are intended for internal networks and are not routed across the public internet. Public addresses are globally routable, subject to routing and network policies.
| Private range | CIDR | Typical use |
|---|---|---|
| 10.0.0.0–10.255.255.255 | 10.0.0.0/8 | Large internal networks |
| 172.16.0.0–172.31.255.255 | 172.16.0.0/12 | Business and private networks |
| 192.168.0.0–192.168.255.255 | 192.168.0.0/16 | Home and small-office networks |
A home router often uses a private address on its local network interface and a separate ISP-assigned address on its internet interface. Network address translation (NAT) commonly allows multiple private IPv4 devices to share an external IPv4 address.
Private addressing does not replace firewalls, access controls, updates, or secure configuration. Devices on the same local network can still pose risks to one another.
IP addresses can be configured manually or assigned automatically. On IPv4 networks, DHCP is commonly used to provide devices with addresses and other network configuration details.
A static address is configured to remain consistent. It may be manually configured or maintained through a DHCP reservation.
Often useful for
A dynamic address is assigned automatically, commonly through DHCP. It can change when a lease expires or the network configuration changes.
Often useful for
Dynamic does not necessarily mean the address changes every day, and static does not guarantee that an address can never change. Actual behavior depends on the administrator, provider, and configuration.
Some IPv4 ranges have special purposes. Recognizing them helps when troubleshooting networks and interpreting security logs.
The 127.0.0.0/8 range is reserved for loopback. The address 127.0.0.1 is commonly called localhost and is used to test services on the same computer without sending traffic to a remote network.
A Windows device may self-assign a link-local IPv4 address when DHCP is unavailable and no other address configuration takes precedence. This can help with communication on the same link, but it usually does not provide ordinary internet connectivity through the failed DHCP configuration.
If you see a 169.254.x.x address unexpectedly, check the network connection, DHCP server or router, and adapter configuration.
Depending on context, 0.0.0.0 can represent an unspecified IPv4 address or be used in routing and service-binding configurations. It is not an ordinary address for reaching a remote host.
This is the IPv4 limited broadcast address, used to reach eligible hosts on the local network segment. Routers do not forward this limited broadcast as ordinary traffic to remote networks.
You can check the addresses configured on your Windows network adapters using Command Prompt or Windows Settings.
cmd and press Enter.ipconfigRun this command in Windows Command Prompt to view your IP configuration.
Find the active Wi-Fi or Ethernet adapter. Look for the IPv4 Address, Subnet Mask, and Default Gateway fields. The IPv4 address shown here is usually the address configured on your computer's local network interface.
The address shown by ipconfig is normally your local interface address. It may differ from the public address seen by a website because your router or provider may use NAT. VPNs and proxy services can also affect which public address a service sees.
Network defenders frequently examine IP addresses when reviewing firewall logs, investigating unusual connections, monitoring servers, or troubleshooting network incidents.
Distinguish source and destination addresses when examining packet captures and connection logs.
Understand which IP addresses or CIDR ranges a rule permits or blocks.
Check whether an interface has a suitable address, subnet mask, and default gateway.
Correlate IP addresses with timestamps, ports, DNS records, device logs, and other evidence.
An IP address alone does not prove who used a device or whether activity was malicious. Addresses may be shared, reassigned, or obscured by NAT, VPNs, or proxies. Defenders must evaluate supporting evidence and context.
Once you understand individual IP addresses, the next step is to learn how addresses are grouped into networks and how IPv4 differs from IPv6.
An IP address is a logical address associated with a network interface. It helps devices and routers identify the source and destination of IP packets.
No. An IP address is used for communication at the Internet Protocol layer, while a MAC address is used for delivery on a local network link. They serve different purposes.
A public IP address is globally routable on the internet. Private IPv4 addresses are reserved for internal networks and are not directly routed across the public internet.
No. A dynamically assigned address may change over time. A static address is intended to remain consistent, although the exact behavior depends on how the network is configured.
127.0.0.1 is the commonly used IPv4 loopback address. It lets a computer communicate with its own local network stack without sending that traffic to another device on the network.
APIPA refers to IPv4 link-local addressing in the 169.254.0.0/16 range. Windows commonly uses such an address when automatic IPv4 configuration through DHCP is unsuccessful and no other configuration takes precedence.
IP Addressing Learning Path
Move from IP address fundamentals to subnet calculations and IPv4/IPv6 networking. Build each concept step by step.