If you have a wireless internet device connected to your laptop, then you can use your laptop as an internet gate way in your LAN . Other computers can access internet through your laptop. If your internet is fast you can run a small office over that wify connection.
Let me explain how it possible.
So you need two NIC’s in your computer and running Linux operating system.
Your Laptop configuration:
wlan0 -> This will be connected to public internet and you can access internet from your laptop
eth0 -> This will connect to your lan or switch , let us assign an ip for it 10.0.0.100
Now perform the following commands.
# echo 1 > /proc/sys/net/ipv4/ip_forward
# /sbin/iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE
# /sbin/iptables -A FORWARD -i wlan0 -o eth0 -m state –state RELATED,ESTABLISHED -j ACCEPT
# /sbin/iptables -A FORWARD -i eth0 -o wlan0 -j ACCEPT
Now go to nearest computer and configure an ip address on range 10.0.0.100/24 , make sure to use gateway ip 10.0.0.100 . You can also use public name servers 126.96.36.199 and 188.8.131.52
Now access internet and surf the world. Enjoy it. If you need to use this after a reboot , make sure the above iptable rules must be saved.