Does everyone on my home network have the same IP address? Also, if someone outside my home network uses my WIFI will they have the same IP address as my computer?
You are all likely sharing the same Internet IP address (which is what shows up on whatismyip.com), but have individual local IP addresses (which is what shows up with ipconfig).
Thanks for your question xxxtexan.
Before an answer could be offered, a basic understanding of "IP Addresses" is necessary.
Your computer actually utilizes three IP Addresses to access the internet if you are using a router which is advisable.
The IP you see when you visit our home page is your External IP. That is assigned by your ISP.
The IP address you see when you type "ipconfig" at a command prompt is your internal IP. Most routers default to 192.168.0.xxx or 192.168.1.xxx.
The third ip address is the IP of the Gateway you use to access the internet. That would be your Router.
If ipconfig showed the following:
IP Address 192.168.1.100
Subnet Mask 255.255.255.0
Default Gateway 192.168.1.1
That means your internal IP address would be 192.168.1.100 and other computers inside you home that are connected to the same router would have similar addresses such as 192.168.1.101 or ...102. This would be the first address needed for internet communication.
The Default Gateway is the router. All of the computers connected to the router would communicate with it to reach the internet which in this case is 192.168.1.1. The Router would then relay the information it gets from each computer to the appropriate website and return the website data to the correct computer. In essence, it routes the internet requests and return data, hence the name Router.
The third address used is the external address mentioned above. That is the WAN or Wide Area Network address of your internet connection. It is YOUR address on the internet. The Router sends all of the internal requests made by your computers out on that external address and receives all of the return data on that same address and then forwards the data to the computer that made the request.
So, to answer your questions:
[I]Does everyone on my home network have the same IP address?[/I] Externally, yes. Internally, no.
[i]if someone outside my home network uses my WIFI will they have the same IP address as my computer? [/i] They will be using YOUR external IP Address but they will also have their own separate internal address such as 192.168.1.103. This does represent a threat to you personally. If they download illegal music or movies, it will show that it was done on YOUR IP address. On a deeper examination, with the help of your ISP through legal channels, you may be able to prove that it was someone outside your home that did the downloads but it will be very difficult.
The best thing to do is secure your WIFI as a method of protecting yourself. I, personally, use MAC address filtering to deny access to all except the ones listed in the Router. Many others would recommend encryption of one type or another.