Find the vendor name of a device by entering an OUI or a MAC address
What is the difference between a MAC address and an IP address?
A MAC address names a network interface. An IP address names a place on a network. The MAC is built into the hardware by whoever made it and stays with the device, while the IP is handed out by the network you join and changes when you join a different one. Both are needed to send a single packet: the IP says where the packet is going, the MAC says which interface on this link should receive it.
Side by side
| MAC address | IP address | |
| Length | 48 bits, six octets | 32 bits (IPv4) or 128 bits (IPv6) |
| Given by | The manufacturer, from a block the IEEE allocated to it | The network, by DHCP, manual configuration or router advertisement |
| Reaches | One link: the devices sharing a cable, a switch or a Wi-Fi network | The whole internet, across routers |
| Changes when | Rarely — the interface is replaced, or the operating system randomizes it | Constantly — every network you join, and often on a timer |
| Example | 00:1A:2B:3C:4D:5E | 192.168.1.20 or 2001:db8::1 |
How they work together
Suppose a laptop wants to reach 192.168.1.20. It knows the IP address, but a frame on an Ethernet or Wi-Fi link cannot be addressed to an IP address — it carries MAC addresses. So the laptop asks the whole link, in effect, "who has this IP address?", and the device that holds it answers with its MAC address. That exchange is the Address Resolution Protocol, and it is the reason the two kinds of address exist side by side: one is what you are trying to reach, the other is how you reach it on this particular link.
Why the MAC does not travel with the packet
When a packet leaves your network, the router strips the link-layer header and builds a new one for the next link, so the MAC addresses in a frame are only ever meaningful between two neighbours. The IP address is what survives from end to end — unless a NAT rewrites it, which is what happens when many devices share one public address.
That is also why the two are looked up in different registries. A MAC prefix is matched against IEEE registration data, which records the organization a block was allocated to. An IP address belongs to the records of the regional internet registry that allocated it, which is why an IP lookup tends to name a provider rather than a company, and never a device.
The one that can be reused
192.168.1.20 is a private address: the same one exists in millions of homes and offices at the same time, because it is never routed on the public internet. MAC addresses are not reused the same way — a manufacturer assigns each one once — but they are not guaranteed unique either, because an operating system may present a different, locally administered address on each network. Is every MAC address unique? covers when that guarantee holds and when it does not.
What each one tells you
Neither identifies a person. A MAC address tells you which organization registered the block the interface came from, which is rarely the brand on the box and never the owner — what a lookup can identify sets out exactly how far that goes. An IP address tells you which network the traffic came from, and often which provider operates it.
To see the registration behind an interface, look up its first six hexadecimal digits in the MAC address lookup; what a MAC address is covers the bits themselves.
Related questions
Sources and review
Last reviewed: . Technical claims on this page follow the primary sources below; operating-system interfaces change between releases, so check them against your own device version.