How to find mac address of devices connected to my modem and block them from my network on ubuntu terminal?

Question

Firstly, I want to thank you as finally I found IP addresses that were connected to my modem. I found out all 5 devices that were connected to my modem using nmap, while it was showing only 2 devices before scanning. I want to find their mac address and remove those devices from my Wi-Fi using Gnome-Terminal. I am able to do this using modem interface but I want to work on Ubuntu and learn Linux, so I want to do this using Terminal. İs it possible? If yes, please tell me how?

possible duplicate of List all MAC addresses and their associated IP addresses in my local network (LAN) — Panther, Sep 29 '15 at 12:43
You can not "kick" them with pc from router. To find mac address on local lan you can use nmap, arp-scan ... but wifi theft connent to router and you must block them on router. — 2707974, Sep 29 '15 at 12:44
Finding out mac address is one step. Second, step would be to set up mac filtering on your router. Third, change the wifi password. And finally set up admin password on the router itself — Sergiy Kolodyazhnyy, Sep 29 '15 at 13:02
@Serg I know I have to mac filtering, change the wifi password. But I want to ask whole of these steps is that possible on linux terminal, because I try to learn linux. Thank you. — m.tuğrul, Sep 29 '15 at 13:04
@m.tuğrul Well, you can find mac addresses through linux terminal with nmap like bodhi shows in his answer, but the wifi router is a different machine, and it may or may not have linux firmware. — Sergiy Kolodyazhnyy, Sep 29 '15 at 13:09
@Serg thank you for your interest. I already found their ip adresses via nmap but nmap didn't show their mac adresses. nmap showed my router mac adress but didn't show other devices'. — m.tuğrul, Sep 29 '15 at 13:12

score 3 · Answer 1 · edited Jul 15 '16 at 22:42

3

You can use nmap with any of several options. The machines must be on the same LAN, no router in between.

nmap -sP
nmap -sn
nmap -sL
nmap -PU

See man nmap and / or: https://nmap.org/book/man-host-discovery.html

edited Jul 15 '16 at 22:42

andrew.46

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answered Sep 29 '15 at 12:41

Panther

102,067

the use of nmap could be classified by administrators as an attack. Use the tool only in your network – A.B. Sep 29 '15 at 12:50
thank you so much, I wanna ask you one more thing. How long nmap scan on your computer? – m.tuğrul Sep 29 '15 at 12:51
Depends on the quantity of systems in your network. – A.B. Sep 29 '15 at 13:09

score 2 · Answer 2 · answered Sep 29 '15 at 13:08

2

If you are interested in using something other than nmap, there is also a tool called tuxcut that lets you scan and block other devices's MAC address connected to the same LAN as yours.
Find the tool here.

answered Sep 29 '15 at 13:08

Sandeep Neupane

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Thank you, Is it work on ubuntu? Can we run it on terminal? – m.tuğrul Sep 29 '15 at 13:13
Yes it works on any Linux system. It actually comes with a Graphical User Interface so you wouldn't be needing to use the terminal. – Sandeep Neupane Sep 29 '15 at 13:23

score 2 · Answer 3 · answered Sep 29 '15 at 13:20

An alternative to nmap would be arp-scan. It's reasonably fast and does give mac addresses. The only limitation it has is that it is only for IPv4 addresses, but for a home network as in your case, this will be OK.

Sample output:

xieerqi:$ sudo arp-scan --interface=eth0 147.153.173.0/24   
Interface: eth0, datalink type: EN10MB (Ethernet)
Starting arp-scan 1.8.1 with 256 hosts (http://www.nta-monitor.com/tools/arp-scan/)
147.153.173.1   3c:df:1e:8c:ed:40   Cisco Systems
147.153.173.16  34:17:eb:c0:21:0f   (Unknown)
147.153.173.20  34:17:eb:c1:29:3e   (Unknown)
147.153.173.21  00:17:f2:05:cb:cc   Apple Computer
147.153.173.21  00:17:f2:05:cb:cc   Apple Computer (DUP: 2)
147.153.173.22  bc:30:5b:d8:9f:ea   Dell Inc.
147.153.173.23  00:22:19:2d:7b:33   Dell Inc
147.153.173.24  34:17:eb:c0:56:cb   (Unknown)
147.153.173.29  34:17:eb:c0:21:76   (Unknown)

thank you. which one is faster? nmap or arp? – m.tuğrul Sep 29 '15 at 13:26 — m.tuğrul, Sep 29 '15 at 13:26
@m.tuğrul definitely arp because it is a very simple scan – Sergiy Kolodyazhnyy Sep 29 '15 at 13:37 — Sergiy Kolodyazhnyy, Sep 29 '15 at 13:37

How to find mac address of devices connected to my modem and block them from my network on ubuntu terminal?

3 Answers3