I studied that MAC addresses are physically printed on network card in the computer, and i also know that there can not be two identical mac addresses in the same network LAN. Now my doubt is:
What happens if there are two Devices with the same MAC address in the same LAN? I think this can happen because even if products print different addresses on the cards, there are software tools with which you can change the MAC address. Is someone's connection blocked or what? Thank you.
Related
While launching ipconfig /all, I can see the description and the physical address (MAC address) of the computers on my computer:
...
Description : Intel ...
Physical address : 48-4D-...
...
Description : Teamviewer VPN adapter
Physical address : 00-FF-...
From the description, I can see which MAC address belongs to my PC and which one belongs to the VPN adapter.
Can I also find this out without reading the description? Is there a way to distinguish VPN related MAC address from "real" ones? (A Windows API answer is preferred, if possible)
There are databases for the MAC addresses, for example from Wireshark.
Since my powershell is utterly bad, I just wrote a small program to iterate over this list and check for a match in the file by Wireshark.
You may check it out and modify as you want: https://github.com/maio290/MacChecker
If no vendor is found for the device, I guess you can assume that this device is a virutal one.
I have a piece of equipment at work that has a USB output, that then requires to be connected to a specific USB-to-Ethernet adapter in order to send TCP packets. I am trying to cut the Ethernet adapter out of the equation, and connect the USB output directly to the computer.
A Windows machine does not detect hardware changes when it's connected, so I'm thinking about using a Ubuntu device since it might have better network tools.
What are the ways I can test the device to figure out what it actually is? Is it even possible to remove the adapter from the equation in this situation?
PS. The device is a very specific ECU used in cars. It is not something I can download drivers for. It also uses a Class C IP address.
if I write 'ipconfig' command in windows 8 command prompt I get lots of physical address under several heading like "wireless lan adapter wi-fi", "ethernet adapter ethernet 2" etc. Under each of these heading there is a physical address and it is completely different from another.
And again if I write 'getmac' command I get a list of 6 physical addresses. I don't understand which one is the real physical address of my laptop. Please let me know how can I find which one is the real mac address of my laptop. Thanks
A laptop doesn't have a MAC address. MAC address is a property of a network interface, such as LAN, WiFi etc. Therefore it is correct that you get different MAC addresses for different adapters.
If you just want to know the MAC address of the adapter currently in use, you can (in Windows 7):
Right-click the connection icon in the system tray
Open Network and sharing center
Next to Connections, click on the connection name.
In the Status window that appears, click Details...
You should then see the physical address of this specific adapter.
You can find screenshots here.
I'm using a Macbook to interface with an ARM development board (Beagleboard xM) over SSH and I use a direct Ethernet connection from the board to my mac. I know I can connect to the board just fine if I know the IP. Usually it will take the next address in line from the last time I connected (e.g. 192.168.2.x -> 192.168.2.x+1), however, sometimes it does not. To find the device on my network I've tried using nmap -sP and -PN, both will return with only the IP of, what I think is, the virtual router on my mac. I have also tried the usual ping 192.168.2.255, this will either return no devices connected or, as mentioned previously, the virtual router.
Does anyone know why it does this or if there is a way for a mac to list all the IPs it is directly connected to over Ethernet (no router, computer to computer)? If I need to I also run Ubuntu 13.04 on my Macbook, so that is an option.
Any suggestions would be greatly appreciated, randomly guessing in the dark at the IP is driving me crazy and scripts I've attempted to make have had no avail.
Thanks!
If you install the avahi daemon on the Beagleboard you should be able to see it between the other Zeroconf devices, thus allowing you to connect to with the name hostname.local, where hostname is the host name of the board.
I had a similar issue, I used the app WaterRoof to figure out what IPs were connected and look for something like what I thought it should be. You may see lots of stuff from places you did not know were connecting to your computer, but I was able to at least narrow it way down and try the few IPs that looked possible, and I got it going. You may try disconnecting/reconnecting the ethernet so it has to renegotiate a connection, and from that you should see it in WaterRoof.
Or maybe this give it to you:
How to determine the IP of the computer that connects to me?
I've been trying write an application which will be able to connect to a network device via rndis or over wifi and perform some simple operations.
The kicker is that I want to be able to find a device I've connected to before, through either connection method. I initially figured I'd just check for a previously seen mac address, but I discovered that the rndis mac address and the wifi mac address don't match. I'm on windows so the next thing I tried was to use nbtstat -A and ping -a, but those didn't turn up anything unique either (I figured I might get a device name, but it doesn't seem to have one).
So my question is, is there any tool (ideally available for windows), which will allow me to retrieve some sort of unique information about a network device that will allow me to find it again? I don't have a huge amount of experience in this field so I'm not sure exactly what that would be, but I hoped that there may be a way to get the mac addresses for both network adapters while only connected to one, or perhaps use a different tool to find a device name that I'd missed.
Thank you for any advice you might give, I really appreciate it. Sorry if I'm overly wordy.
EDIT: In case I've been ambiguous. I am connecting repeatedly to an external device via RNDIS or WIFI from my desktop PC. My goal is to be able to consistently recognize the network device regardless of the connection method used.
EDIT: By networked device, I mean that I have small independant devices (such as cell phones or tablets) running a unix os, which I access from my Windows desktop via wifi or rndis, and that I would like to be able to consistently identify. So for example I might want to use this tool to connect to one of two cell phones and be able to recognize which one it is so I can recall previous operations performed with that device. So what I'm looking for is a unique (or semi unique) attribute of the cellphone available to me that is consistent when accessed via rndis or wifi.
You can get MAC address (and bunch of other network interface info) with built-in ipconfig command and parse its output later:
ipconfig /all
Alternatively, if MAC address is all you need, try getmac.