What is the Difference Between an IP Address and a MAC Address?

MAC address and IP address are both commonly discussed terms in computer networking. 

Every device connected to the internet has both types of addresses (IP address and a MAC address), each serving a different purpose.

In this blog post, we are going to walk you through the differences between an IP address and a MAC address. Read on to know what each one is, how each is formed and used, how they relate and work together in modern networks.

What Is an IP Address?

An IP address (Internet Protocol address) is a set of logical numbers that are assigned to network interfaces primarily for identification purposes. 

Devices use IP addresses to find and talk to each other across networks. Here are some key characteristics of IP addresses:

• They are not permanently bound to hardware. 
• They are logical and changeable.
• Interpreted by network software and routing systems. 

Types of IP Addresses

IP addresses are usually categorized into two types:

IPv4 is a 32-bit numeric address written as four decimal octets, e.g., 192.xxx.x.x. These usually range from 0.0.0.0 to 255.255.255.255. In general, IPv4 addresses are thought to support around 4.3 billion addresses, with some reserved. 

IPv6, on the other hand, is a 128-bit address written in hex groups separated by colons, for example, 2001:0db8:85a3::xxxx:xxxx:xxxx. These are created to solve IPv4 exhaustion. IPv6 provides an unimaginably vast address space, offering 2¹²⁸ possible addresses, roughly 340 undecillion (about 3.4 × 10³⁸), or more precisely 340,282,366,920,938,463,463,374,607,431,768,211,456 unique IP addresses.

To learn more about IPv4 and IPv6 addresses and how they work, check out our blog post on the topic IPv4 vs IPv6 addresses. 

Public vs Private IP Addresses

A public IP address is the one that your internet service provider assigns to your device. Your device communicates (sends and receives data) over a global network (the internet) using this public IP. You can check a device's public IP by visiting our What is My IP tool while using the same device. 

Private IP addresses, on the other hand, are those that are assigned to your devices by the router using the DHCP protocol. Devices on the local network use this private address to communicate with each other. Know that this address remains within your local network and is non-routable over the internet. 

Dynamic vs Static IP Addresses

Based on how IP addresses are assigned to devices, they are further categorized into two types:

• Dynamic
• Static

1: Dynamic IP Addresses

Dynamic IP addresses are those that change over time. For example, if your router's IP address changes each time you restart it, it has a dynamic IP address. It is assigned automatically by a DHCP server (usually your router or your internet service provider).

Here’s how dynamic IPs usually work:

When a device connects to a network, it requests an IP address. The DHCP server looks at its pool of available addresses and assigns one. The assignment is temporary and comes with a lease time (expires after minutes, hours, or days).

When the lease expires, the device can:

• Renew the same IP
• Or receive a totally different IP, depending on availability

2: Static IP Addresses

A static IP address is one that never changes and remains fixed until someone changes it manually. Network service providers usually assign these addresses. Static IPs are used for servers, network equipment, or when a stable address is required.

Which Network Layer Uses IP Addresses?

IP addresses operate at OSI Layer 3 (Network Layer) and are used by routing protocols to forward packets across networks. IP is the canonical Layer-3 protocol in the Internet Protocol Suite.

What is MAC Address?

A MAC Address (that stands, Media Access Control Address) is a unique alphanumeric identifier assigned to a network interface card (NIC) by its manufacturer. This address is used to identify devices on the local broadcast domain (i.e., the local area network). 

MAC addresses are used by switches and by link-layer protocols to deliver frames to the correct physical device on the same local network. Using MAC addresses, you can perform a MAC address lookup to identify the device's vendor information, including the manufacturer's name and address. 

Structure of a MAC Address

A typical MAC address is 48 bits (6 bytes), often shown in hex: AA:BB:CC:DD:EE:FF. 

The structure of the MAC address involves two main components:

• OUI (Organizationally Unique Identifier): These are the first 24 bits (3 bytes) that identify the vendor/manufacturer.
• NIC-specific part: Other than the OUI, these are the remaining 24 bits that the manufacturer allocates to ensure uniqueness.

Types of MAC Addresses

Based on how MAC addresses are assigned and how they are used, they are typically divided into three types. 

1: Unicast MAC Address

A Unicast MAC address is used to identify a specific single device on a network. It is used for one-to-one communication with a particular device. 

Example format:

• 00:1A:2B:3C:xx:xx

When a unicast MAC address is in use, the traffic is directed to only one NIC/device. Most MAC addresses you see on computers, routers, and phones are unicast.

2: Multicast MAC Address

A multicast MAC address is used for one-to-many communication. It is meant to send data frames to a group of devices on a local network. This means the traffic will be sent only to devices in the multicast group. 

Example:

• 01:00:5E:xx:xx:xx

3: Broadcast MAC Address

This MAC address is used for all communication. In this type, traffic with data frames is sent to all devices connected to a single local network. 

Example:

• FF:FF:FF:FF:FF:FF

Which Network Layer Uses MAC Addresses?

MAC addresses are used by the Data Link Layer (OSI Layer 2). Also, Ethernet and Wi-Fi use MAC addresses in frame headers.

MAC Address vs IP Address - Key Differences

Both MAC and IP addresses help computers communicate, but they work in different ways and serve different purposes. 

Why Do Networks Need Both an IP Address and a MAC Address?

Both IP addresses and MAC addresses serve two complementary functions that are necessary for a network's end-to-end communication. The role of a MAC address is to ensure link-local delivery, while the role of an IP address is to ensure end-to-end delivery. 

MAC addresses are responsible for delivering a frame from one NIC to another NIC on the same link. Network switches use them to learn the association between MAC and physical switch ports.

On the other hand, IP addresses are meant to provide logical addressing so routers can forward packets from the source network to the destination network across multiple hops.

Frequently Asked Questions

Can two devices have the same IP address?

Yes, two devices can have the same IP address, but not on the same subnet. If two devices on the same LAN are configured with the same IP address, an IP address conflict will occur. Additionally, on the Internet, two devices cannot share the same public IP address unless NAT is used (multiple internal hosts share a single public IP via NAT).

Can two devices have the same MAC address?

MAC addresses are supposed to be unique for each NIC. However, sometimes duplicate MAC addresses occur. This usually occurs due to defective NICs or manual MAC spoofing. 

Does the MAC address affect internet speed?

No, the MAC address does not directly affect your internet speed. However, misconfigured or duplicate MAC addresses can disrupt connectivity.