How would y'all communicate with a device when you don't have the IP?

You might be in a situation where you don't have the IP accost of a device in a local network, simply all you lot have is records of the MAC or hardware address.

Or your computer is unable to display its IP due to various reasons, and you are getting a "No Valid IP Accost" error.

Finding the IP from a known MAC address should be the task of a ReverseARP application, the counterpart of ARP. Just RARP is an obsolete protocol with many disadvantages, then it was quickly replaced by other protocols similar BOOTP and DHCP, which deal straight with IP addresses.

In this article, we'll show you lot how to find all ip addresses on a network along with device vendors using MAC addresses with dissimilar methods for free.

Find Device IP Using Mac Address

Related post: How to Scan network for IP Addresses

Understanding ARP

ARP (Address Resolution Protocol) is the protocol in charge of finding MAC addresses with IPs in local network segments.

It operates with frames on the data link layer. Every bit you might already know, devices in the data link layer depend on MAC addresses for their advice. Their frames encapsulate packets that contain IP accost data.

A device must know the destination MAC accost to communicate locally through media types similar Ethernet or Wifi, in layer 2 of the OSI model. Understanding how ARP works tin can assistance you notice IPs and MAC addresses quickly.

The post-obit message flow diagram can help you sympathize the concept:

Understanding ARP flow diagram

  • The local computer sends a ping (ICMP echo asking) to a destination IP accost (remote reckoner) inside the same segment. Unfortunately, the local computer does not know the MAC address…  it only knows the IP address.
  • The destination hardware address is unknown, and so the ICMP repeat asking is put on hold. The local reckoner only knows its source/destination IP and its source MAC addresses. ARP uses 2 types of letters, ARP Asking and Answer.

ARP Packet Format

The local figurer sends an ARP REQUEST message to find the possessor of the IP address in question.

This message is sent to all devices inside the aforementioned segment or LAN through a broadcast MAC (FF:FF:FF:FF:FF:FF) every bit the destination.

  1. Because the remote calculator is office of the same network segment, it receives the broadcast message sent by the local computer. All other computers in the LAN also receive the broadcast but they know that the destination IP is not theirs, so they discard the packet. Only the remote computer with destination IP, responds to the ARP Request with an ARP REPLY, which contains the target MAC address.
  2. The local estimator receives the ARP REPLY with the MAC accost. It and so resumes the ICMP echo request, and finally, the remote computer responds with an ICMP echo reply.

Finding IPs with ARP

You lot can employ ARP to obtain an IP from a known MAC address.

Just start, it is important to update your local ARP tabular array in order to get information from all devices in the network.

  • Send a ping (ICMP echo reply) to the entire LAN, to go all the MAC entries on the table.
  • To ping the entire LAN, you can send a broadcast to your network.
  • Open the Command Prompt in Windows or terminal in macOS and type.
ping 192.168.0.255

My subnet is 192.168.0.0/24 (mask of 255.255.255.0), so the circulate address is 192.168.0.255 which tin be calculated or found with a "Impress Road" control in Windows or a "netstat -nr" in macOS. Or can also be obtained with a subnet estimator that you can download for free.

Subnet Calculator

For Windows:

Pace 1

  • Open the CMD (Command Prompt)
  • Go to the "Start" carte and select "Run" or press [Windows-primal] + [R] to open the Run application
  • In the "Open" textbox type "cmd" and printing "OK".

Run CMD

This will open up the command-line interface in Windows.

Stride 2

  • Enter the "arp" command.
  • The arp control without any additional arguments will requite you a list of options that you lot tin can use.Windows System

Pace three

  • Use the arp with additional arguments to find the IP within the aforementioned network segment.
  • With the command "arp -a" y'all tin can meet the ARP tabular array and its entries recently populated by your estimator with the circulate ping.System32

Footstep 4.

  • Reading the output.
  • The data displayed in the arp-a is basically the ARP tabular array on your computer.
  • It shows a list with IP addresses, their respective physical accost (or MAC), and the type of resource allotment (dynamic or static).

Let'due south say you lot have the MAC address 60-30-d4-76-b8-c8 (which is a macOS device) and you want to know the IP.

From the results shown in a higher place, you can map the MAC address to the IP address in the same line.

The IP Address is 192.168.0.102 (which is in the same network segment) belongs to 60-thirty-d4-76-b8-c8.

You can forget near those 224.0.0.x and 239.0.0.ten addresses, as they are multicast IPs.

For macOS:

Step i

  • Open the Terminal App. go to Applications > Utilities > Terminal or Launchpad > Other > Concluding. Terminal App

Footstep 2

  • Enter the "arp" command with an "-a" flag.
  • Once you enter the command "arp -a" you lot'll receive a listing with all ARP entries to the ARP Table in your estimator.
  • The output will show a line with the IP address followed by the MAC address, the interface, and the allocation type (dynamic/static).arp command

Finding IPs with the DHCP Server

The Dynamic Host Configuration Protocol (DHCP) is the network protocol used by TCP/IP to dynamically allocate IP addresses and other characteristics to devices in a network. The DHCP works with a client/server mode.

The DHCP server is the device in charge of assigning IP addresses in a network, and the client is normally your estimator.

For home networks or LANs, the DHCP Server is typically a router or gateway.

If you have access to the DHCP Server, yous can view all relationships with IPs, MACs, interfaces, name of the device, and lease fourth dimension in your LAN.

Step 1

  • Log into the DHCP Server. In this example, the DHCP server is the abode gateway.
  • If you don't know the IP address of your DHCP Server/ Gateway, you can run an ipconfig (in Windows) or ifconfig (in macOS/Linux)open a command prompt
  • This particular DHCP Server/Gateway has a web interface.

Stride 2

  • Enter the IP address on the search bar of the web browser, and input the correct credentials.

Step 3

  • Notice the DHCP Clients List.
  • In this TP-Link router, the DHCP Server functionality comes equally an boosted characteristic.
  • Go to DHCP > DHCP Clients Listing. From this list, you can see the mapping between MAC addresses and their assigned IPs.

Using Sniffers – Nmap

If you lot couldn't notice the IP in the ARP listing or unfortunately don't have access to the DHCP Server, as a concluding resort, you can use a sniffer.

Packet sniffers or network analyzers like Nmap (or Zenmap which is the GUI version) are designed for network security.

They can help place attacks and vulnerabilities in the network.

With Nmap, you can actively scan your unabridged network and find IPs, ports, protocols, MACs, etc.

If yous are trying to find the IP from a known MAC with a sniffer like Nmap, look for the MAC accost within the scan results.

How to find the Device and IP with a Sniffer?

Step 1

  • Keep records of your network IP address data.
  • In this case, my network IP is 192.168.0.0/24. If yous don't know it, a quick "ipconfig" in Windows cmd or an "ifconfig" in macOS or Linux terminal tin can show you the local IP and mask.
  • If you can't subnet, Download this Free Subnet Calculator tool or go online to a subnet computer and observe your network IP.

Step 2

  • Download and open Nmap.
  • Download Nmap from this official link https://nmap.org/download.html and follow its straightforward installation process.

Step iii

  • Open up Nmap (or Zenmap) and use the command "sudo nmap -sn (network IP)" to scan the entire network (without port scan).
  • The command will list machines that answer to the Ping and will include their MAC address along with the vendor.
  • Don't forget the "sudo" command.
  • Without information technology, you will not see MAC addresses.nmap

Finding out the device vendor from a MAC address

Ok, and then now you were able to find out the IP accost using "arp -a" command or through the DHCP Server.

But what if you want to know more details about that item device?

What vendor is it?

Your network segment or LAN might be full of different devices, from computers, firewalls, routers, mobiles, printers, TVs, etc.

And MAC addresses contain primal information for knowing more details virtually each network device.

Commencement, it is essential to understand the format of the MAC address.

Traditional MAC addresses are 48 bits represented in 12-digit hexadecimal numbers (or six octets).

The outset one-half of the half-dozen octets represent the Organizational Unique Identifier (OUI) and the other half is the Network Interface Controller (NIC) which is unique for every device in the world.

6 octets

There is not much we can exercise about the NIC, other than communicating with it.

Only the OUI can give us useful data virtually the vendor if y'all didn't utilize Nmap, which tin too give you the hardware vendor.

Using Wireshark OUI Lookup

A free online OUI lookup tool like Wireshark OUI Lookup can help you with this.

Merely enter the MAC address on the OUI search, and the tool will await at the get-go three octets and correlate with its manufacturing database.

Using Wireshark OUI Lookup

Using DHCP to view IP info

Although the RARP (the counterpart of ARP) was specifically designed to find IPs from MAC addresses, it was quickly discontinued because it had many drawbacks.

RARP was chop-chop replaced by DHCP and BOOTP. But ARP is notwithstanding one of the core functions of the IP layer in the TCP/IP protocol stack. Information technology finds MAC addresses from known IPs, which is most mutual in today's communications. ARP works under the hood to keep a frequently used list of MACs and IPs.

But you can as well use information technology to see the electric current mappings with the command arp -a.

Aside from ARP, you can also apply DHCP to view IP data. DHCP Servers are usually in charge of IP assignments. If you lot have access to the DHCP server, go into the DHCP Client listing and identify the IP with the MAC address. Finally, yous can use a network sniffer similar Nmap, scan your unabridged network, and find IPs, and MACs.

If y'all only want to know the vendor, an online OUI lookup like Wireshark tin assistance you notice it rapidly.

Detect a Device or IP Accost FAQs

Can yous find an IP accost from a MAC address?

Yes. Open a Command Prompt window and enter the command arp -a. The output shows all of the IP addresses that are active on your network. The adjacent column in the output is headed Physical Accost. This is the MAC address. Look for the line in the output that has the MAC accost that you know and note down the IP address on that line.

How can I access a device by MAC address?

The easiest fashion to admission a device, knowing the MAC address is to utilize the arp -a control to notice the related IP address. With this accost, you lot can access the device using Remote Desktop Direction, a Telnet program, or another connection facility.

How can I observe a device by IP address? (cmd instructions)

You tin can follow a path to a device if y'all know its IP accost past using the tracert command at the command prompt (cmd). Open a Command Prompt window and type in tracert followed past the IP address that you lot know. The output will prove each router that has a connectedness to that device will pass through.