What Is an IP Address? Public vs Private, IPv4 vs IPv6, and What Websites Can See
A practical explanation of IP addresses, including public vs private addressing, IPv4 vs IPv6, NAT, and what websites can realistically infer from your connection.
If you have ever searched for what is my IP, you were really asking a bigger question:
- what address is visible to the internet
- what does that address reveal
- and how is it different from the address on my own device
That starts with understanding what an IP address is.
What an IP address actually does
An IP address is a network identifier that helps systems send traffic to the right destination.
Think of it as a routing label, not a personal identity card.
At a high level, it helps answer:
- where should packets go
- which network announced this route
- which connection is talking to a service right now
IPv4 vs IPv6
There are two major versions of IP addresses in everyday use.
IPv4
IPv4 is the older format and looks like this:
203.0.113.24
It uses 32-bit addresses, which created long-term scarcity.
IPv6
IPv6 is the newer format and looks like this:
2001:db8::42
It uses 128-bit addresses and was designed to solve IPv4 exhaustion and reduce some of the complexity caused by heavy NAT use.
If you want a deeper IPv6-specific walkthrough, read IPv6 Explained.
Public vs private IP addresses
This is the part most people miss.
Private IP address
A private IP is used inside your local network. Common examples:
192.168.x.x10.x.x.x172.16.x.xthrough172.31.x.x
These addresses are not intended to be globally routable on the public internet.
Public IP address
A public IP is the address the internet usually sees when traffic leaves your network. That may belong to:
- your ISP
- your mobile carrier
- your VPN provider
- your proxy service
- a hosting or cloud network
If this distinction is still fuzzy, read Public vs Private IP Addresses.
Why one home can have many devices but one public IP
That is usually because of NAT, or Network Address Translation.
NAT lets many local devices share one outward-facing public IP. That is why:
- one IP can represent many users
- one user can appear under different IPs over time
- IPs are useful network clues, but weak personal identifiers
What websites can usually infer from your IP
An IP lookup can often reveal:
- approximate country, region, or city
- ISP or carrier
- ASN and route-origin organization
- whether the IP looks more residential, mobile, corporate, or hosting-related
- possible VPN, proxy, or data-center indicators
What websites usually cannot infer reliably
- your exact street address
- your name
- whether one IP always equals one person
That is why IPs work best as network context, not identity proof.
Why ASN matters in an IP lookup
When people ask “who owns this IP?”, the most useful answer often starts with the ASN and network organization rather than the geolocation alone.
That helps you answer:
- which provider announces this range
- whether this looks like consumer broadband or hosting infrastructure
- where to start if you need routing or abuse context
For that workflow, continue with How to Find the ISP From an IP Address and ASN Lookup Guide.
Why your IP can appear to change
Your internet-facing IP can change because of:
- ISP reassignment
- mobile network pooling
- VPN or proxy use
- switching between Wi-Fi and cellular
- data-center or anycast routing changes
So if your location or ASN looks different after connecting through a VPN, that is usually expected.
A practical workflow
If you want to understand what your IP is actually telling a website, use this sequence:
- Run the IP lookup tool.
- Confirm whether you are seeing IPv4 or IPv6.
- Check the ASN and network owner.
- Decide whether the address looks residential, mobile, corporate, or hosting-related.
- If needed, pivot into the related guides on proxy/VPN classification, public vs private addressing, or ISP attribution.
FAQ
Is an IP address the same as a device ID?
No. An IP identifies a network path or egress point more than a single device identity.
Can two users share one public IP?
Yes. That is common with home routers, office gateways, mobile carriers, and VPN exits.
Does IPv6 mean I no longer need to care about private vs public addressing?
No. IPv6 changes how addressing works, but internal-only ranges, route scope, and privacy behavior still matter.
What should I check first when an IP result looks strange?
Check whether you are on VPN, proxy, mobile data, or dual-stack IPv4/IPv6 connectivity. Those are often the fastest explanations.
Continue reading
Stay in the same investigation track with these closely related guides.
Tools mentioned in this article
Run the same diagnostics to follow along with the guide.