Linux Mac Address For Ip

Mar 04, 2020 The IP address responds and sends back acknowledgments to the pings. Our new IP address is up and running after one simple ip command. Deleting an IP Address. To delete an IP address, the command is almost the same as the one to add one, except you replace add with del, as shown below: sudo ip addr del 192.168.4.44/24 dev enp0s3. Aug 18, 2016 Find MAC address in Linux. First, let us find out the MAC address or Hardware address of a Network interface card in Linux. $ ifconfig grep HWaddr. Sample output: enp0s3 Link encap:Ethernet HWaddr 08:xx:xx:xx:xx:x1. Or, $ ip link show.

  1. Get Mac Address On Linux
  2. Linux Mac Address Change
  3. Linux Mac Address For Ipod

May 12, 2020 Method 3: How to find MAC Address in Linux Using ip addr sh command. If you want to check the MAC address of all the network interfaces then you need to simply use ip addr sh command and check the MAC address from ether field as shown below. The MAC address, also known as the Media Access Control address, is the unique and separate hardware number of a particular computer, especially in a LAN (Local Area Network) or other network. When connected to the internet as a host or your computer is connected to the Internet, the IP address of your computer is linked to the physical MAC. The MAC address, also known as the Media Access Control address, is the unique and separate hardware number of a particular computer, especially in a LAN (Local Area Network) or other network. When connected to the internet as a host or your computer is connected to the Internet, the IP address of your computer is linked to the physical MAC.

This article discusses the MAC address, including how to spoof your system’s MAC address. This article will show you which steps are important to consider while changing the MAC address of your device. In addition, we will discuss some of the key instructions and proper guidance for changing the MAC address. First, we will start with a basic definition of the MAC address.

Media Access Control (MAC) Address


The MAC address, also known as the Media Access Control address, is the unique and separate hardware number of a particular computer, especially in a LAN (Local Area Network) or other network. When connected to the internet as a host or your computer is connected to the Internet, the IP address of your computer is linked to the physical MAC address of the computer on a LAN. A MAC address is similar to an Ethernet address on the Ethernet LAN. In telecommunication protocols, the media access control, which is the sublayer of the data-link layer, uses the MAC address.

Changing the MAC Address with macchanger in Kali Linux

To follow this tutorial to change the MAC address in Kali Linux by using macchanger, the following points are important to consider:

Key Objective

The key objective of this article is to change the real hardware MAC address of the network’s card. This article will show you how to change the MAC address with the help of macchanger in Kali Linux.

Main Requirements

The main essential requirement is to have authorized access to a system having Kali Linux.

Level of Difficulty

The difficulty level must be easy.

Protocol

# (needs to execute given Linux commands with authorized roots, instead of using the sudo command, or needs to be done directly by the root user)

$ (involves the execution of given Linux commands as the non-authorized user)

Key Instructions

The following key instructions will be included in this tutorial:

  • Changing the MAC address to a random MAC address
  • Checking the new MAC address
  • Changing the MAC address to a specific MAC address

Change the MAC Address to a Random MAC address

In the first step, we will use macchanger to change the hardware MAC address of the network card to a random address. We will investigate the current MAC address by taking the eth0 network interface. By doing so, we will able to execute the macchanger with the argument eth0 and the option -s.

The network interface must be turned off before changing the MAC address. The command ifconfig is used to turn off the interface of the network. This command is shown below:

If you have failed to turn off the network interface, then the following error message will be displayed:

Disco for mac. ERROR: Can’t change MAC: interface up or not permission: Cannot assign requested address

Now, we will change the hardware MAC address of the network card to different hexadecimal numbers. You can do so by entering the following command:

Finally, bring up the network interface and show your new MAC address by entering the following commands:

Check the New MAC Address

After listing the network interface with the help of the ifconfig command, the new MAC address will be shown.

Change the MAC Address to a Specific MAC Address

To change the MAC address to a specific string in Kali Linux, use the following method. This can be done with the help of macchanger’s -m option. The commands for changing the MAC address to a specific address are given below:

Now, use the -1 option to determine the MAC address prefix for the particular hardware vendor. The command will be written as follows:

Conclusion

This tutorial explained what a MAC address is and how one can spoof it using the macchanger and ifconfig commands.

How would you communicate with a device when you don’t have the IP?

You might be in a situation where you don’t have the IP address of a device in a local network, but all you 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 Address” error.

Finding the IP from a known MAC address should be the task of a ReverseARP application, the counterpart of ARP.

But RARP is an obsolete protocol with many disadvantages, so it was quickly replaced by other protocols like BOOTP and DHCP, which deal directly with IP addresses.

In this article, we’ll show you how to find IPs and device vendors using MAC addresses with different methods for free.

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.

As you might already know, devices in the data link layer depend on MAC addresses for their communication.

Their frames encapsulate packets that contain IP address information.

A device must know the destination MAC address to communicate locally through media types like Ethernet or Wifi, in layer 2 of the OSI model.

Understanding how ARP works can help you find IPs and MAC addresses quickly.

The following message flow diagram can help you understand the concept:

  1. The local computer sends a ping (ICMP echo request) to a destination IP address (remote computer) within the same segment. Unfortunately, the local computer does not know the MAC address… it only knows the IP address.
  2. The destination hardware address is unknown, so the ICMP echo request is put on hold. The local computer only knows its source/destination IP and its source MAC addresses. ARP uses two types of messages, ARP Request and Reply.

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

Address

This message is sent to all devices within the same segment or LAN through a broadcast MAC (FF:FF:FF:FF:FF:FF) as the destination.

  1. Because the remote computer is part 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 computer receives the ARP REPLY with the MAC address. It then resumes the ICMP echo request, and finally, the remote computer responds with an ICMP echo reply.

Finding IPs with ARP

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

But first, it is important to update your local ARP table in order to get information from all devices in the network.

Send a ping (ICMP echo reply) to the entire LAN, to get 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 broadcast address is 192.168.0.255 which can be calculated or found with a “Print Route” command in Windows or a “netstat -nr” in macOS. Or can also be obtained with a subnet calculator.

For Windows:

Step 1.

  • Open the CMD (Command Prompt)
  • Go to the “Start” menu and select “Run” or press (Windows key + R) to open the Run application
  • In the “Open” textbox type “cmd” and press “Ok”.

This will open the command-line interface in Windows.

Step 2.

  • Enter the “arp” command.
  • The arp command without any additional arguments will give you a list of options that you can use.

Step 3.

  • Use the arp with additional arguments to find the IP within the same network segment.
  • With the command “arp -a” you can see the ARP table and its entries recently populated by your computer with the broadcast ping.

Step 4.

  • Reading the output.
  • The information displayed in the arp-a is basically the ARP table on your computer.
  • It shows a list with IP addresses, their corresponding physical address (or MAC), and the type of allocation (dynamic or static).

Let’s say you 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 above, 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 60-30-d4-76-b8-c8.

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

For macOS:

Step 1:

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

Step 2:

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

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 usually your computer.

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

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

Step 1.

  • Log into the DHCP Server. In this example, the DHCP server is the home 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).
  • This particular DHCP Server/Gateway has a web interface.

Step 2.

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

Step 3.

  • Find the DHCP Clients List.
  • In this TP-Link router, the DHCP Server functionality comes as an additional feature.
  • Go to DHCP > DHCP Clients List. From this list, you can see the mapping between MAC addresses and their assigned IPs.

Using Sniffers

If you couldn’t find the IP in the ARP list or unfortunately don’t have access to the DHCP Server, as a last 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 identify attacks and vulnerabilities in the network.

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

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

How to find the Device and IP with a Sniffer?

Step 1.

  • Keep records of your network IP address information.
  • In this case, my network IP is 192.168.0.0/24. If you don’t know it, a quick “ipconfig” in Windows cmd or an “ifconfig” in macOS or Linux terminal can show you the local IP and mask.
  • If you can’t subnet, go online to a subnet calculator and find 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 3.

  • Open 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 respond to the Ping and will include their MAC address along with the vendor.
  • Don’t forget the “sudo” command.
  • Without it, you will not see MAC addresses.

Finding out the device vendor from a MAC address

Ok, so now you were able to find out the IP address using “arp -a” command or through the DHCP Server.

But what if you want to know more details about that particular 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 key information for knowing more details about each network device.

First, 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 first half of the six 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.

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

But the OUI can give us useful information about the vendor if you didn’t use Nmap, which can also give you the hardware vendor.

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

Just enter the MAC address on the OUI search, and the tool will look at the first three octets and correlate with its manufacturing database.

Final Words

Get Mac Address On Linux

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 quickly replaced by DHCP and BOOTP.

But ARP is still one of the core functions of the IP layer in the TCP/IP protocol stack.

It finds MAC addresses from known IPs, which is most common in today’s communications.

ARP works under the hood to keep a frequently used list of MACs and IPs.

But you can also use it to see the current mappings with the command arp -a.

For

Linux Mac Address Change

Aside from ARP, you can also use DHCP to view IP information. DHCP Servers are usually in charge of IP assignments.

Linux Mac Address For Ipod

If you have access to the DHCP server, go into the DHCP Client list and identify the IP with the MAC address.

Finally, you can use a network sniffer like Nmap, scan your entire network, and find IPs, and MACs.

If you only want to know the vendor, an online OUI lookup like Wireshark can help you find it quickly.