View Full Version : How to tell if you have a Private IP Address or a Public IP Address

I use Nirsoft's netrouteview because it has a GUI: http://www.nirsoft.net/utils/network_route_view.html

Private IP Addresses have the following ranges: - - -

I've difficulty understanding the reason for your comment.

Don't you take into account machines that have a public IP address on their NIC?
I've seen several posts here where it turned out the user's machine had a public IP address, and not a private IP address.
And these people have problems figuring this out.
They often go to a site like "what is my IP address", but this doesn't answer the question.
That is why I made my video.

As to using private IP addresses on a LAN: this is just a convention, it is not mandatory. You can use public IP addresses on your LAN, and then NAT them to another public IP address to access the Internet.

The association between a private and public IP address in case of NAT is done at the level of the device that does the NATing. Usually based on port NATing.
This association is not explicited in the PC.

Are you asking for replies? It's not clear whether you are or not. Mine's private, assigned by my router via DHCP. At least that's what it is at home. I never check it when I'm at a public place where I use my tablet (Google Nexus 7) which has no sensitive info on it.

No, not asking for replies. This is for later reference: when I have to help somebody and need to know if they have a private or public ip address, I'll direct them to this post if they don't know how to determine this.

The subject of your post is a question. You should change it to something like "How to tell if....".

Although RFC-1918 specifies these as "PRIVATE IP ADDRESSES": - - -

The story is incomplete.

"PRIVATE IP ADDRESSES" are for the internal networks and "PUBLIC IP ADDRESSES" are what is seen on the Internet.

For instance, the computers on my home network is:

my laptop
wife's laptop

But going out to the world, the "PUBLIC IP ADDRESSES" is 75.x.x.x.

COX said it best (empasis added by scotty_ncc1701)