The problem is the following : I am using have a standard Raspberry PI (i.e. without any WIFI interface) at a location where the only way to access the Internet is the WIFI. Is it possible to use my portable PC running Windows as a router to connect the Raspberry PI to the Internet ?
The answer is YES and it is very easy
Step1: Activate ICS
Activate the ICS on the WIFI connection of the Windows computer. The ICS (Internet Connection Sharing) allows other computers to use the WIFI connection of the Windows computer.
This is done in the network control panel (you may reach it by using the command)
And then activate the sharing of the the WIFI connection
Once this is done any computer connected to the PC ethernet port shall receive via DHCP an IP address in the 192.168.137.X network (note the PC is located at 192.168.137.1)
Step2 Connect the Raspberry PI to the PC
Connect the Raspberry PI with a standard Ethernet cable equipped with standard RJ45 connectors). You don't even need a crossed cable because the Raspberry PI support auto MDI-X (which means that the Raspberry PI will detect that a crossed cable is needed and automatically preform the « cross » internally) .
Now everything is done and your raspberry PI can access the Internet. But If You don't have keyboard and display connected to it you need to know which IP address the Windows PC DHCP has given to it.
Step 3 retrieve the Raspberry PI IP address
The simplest way to obtain this address is to query the ARP table. Start a Windows command prompt (if you don't know how to do it just press WINDOWS+R and type cmp ENTER)
and type the following command
arp -a -N 192.168.137.1
This will give you a reply that looks like that
In this list you see that the Rasberry PI has been granted the addres 192.168.137.55
Note : the 192,168,137,255, all the 224.x.x.x and the 126.96.36.199 addresses are all multicast addresses (we don't care about them)
You can now connect to you Rasberry PI via SSH and from the Raspberry PI communicate with the Internet.