What Is an IP Address? Public IP, Private IP, IPv4, and IPv6 Explained

Most people encounter the term "IP address" when something goes wrong — a site is blocked, a VPN isn't working, or an IT department asks "what's your IP?" It sounds technical, but the concept is straightforward once you have the right analogy.

Think of your IP address as your device's postal address on the internet. Just as a letter needs a return address and a destination address, internet traffic needs to know where it came from and where it's going. IP addresses make that possible.

IPv4 vs IPv6 — what's the difference?

IPv4

Format: 192.168.1.1

Four groups of numbers (0–255) separated by dots. About 4.3 billion possible addresses — which have been exhausted globally since around 2011. Most internet traffic still uses IPv4.

IPv6

Format: 2001:db8::1

Eight groups of hexadecimal digits. About 340 undecillion possible addresses. IPv6 adoption is growing as IPv4 runs out, but both coexist on the modern internet.

If you check your IP address and see a long string of numbers and colons, that is IPv6. A dotted decimal like 203.0.113.1 is IPv4. Most modern devices support both.

Public IP vs Private IP

You actually have two kinds of IP addresses on most home networks. Understanding the difference explains a lot of confusing behavior.

	Public IP	Private IP
Who assigns it	Your ISP (KT, SKT, LG U+, etc.)	Your home router
Visible to	The entire internet	Only devices inside your home network
Example	203.0.113.55	192.168.1.5, 10.0.0.3
Unique?	Yes — globally unique	No — reused across millions of home networks

Your phone and laptop at home share the same public IP (your router's address to the internet), but have different private IPs within your home network. When a website logs your IP, it sees the public one.

What VPNs actually do to your IP

A VPN (Virtual Private Network) creates an encrypted tunnel between your device and a server in another location. All your internet traffic goes through that server. The result:

Websites see the VPN server's IP address, not your real one.
Your apparent location becomes wherever the VPN server is located.
Your real public IP is hidden from the websites you visit.

This is why VPNs can access region-restricted content — if the VPN server is in the US, you appear to websites as a US user.

Important caveat: your ISP can still see that you are connecting to a VPN server, even if they cannot see the content. And your VPN provider can see your traffic. VPNs shift trust, they do not eliminate it.

Does my IP address change?

Most home internet connections use a dynamic IP — your ISP can change your public IP when you reconnect or at regular intervals. This is why your IP address today might be different from last week.

Business internet connections often use a static IP that never changes. This is more expensive but necessary for hosting servers, running remote access services, or other cases where people need to reach your IP reliably.

To check your current public IP at any moment, an IP lookup tool shows it in one click — useful before and after connecting a VPN to verify it is working.

What can someone do with your IP address?

Less than most people fear, more than nothing. Here is an honest breakdown:

Approximate location: Your IP can usually be traced to your city, and sometimes your ISP. Not your street address or exact location.
DDoS attacks: Someone with your IP could flood your connection with traffic (a DDoS attack). This is rare for individuals but common for gaming servers and online services.
What they cannot do: Access your device, hack your accounts, see your browsing history, or find your physical address. An IP address alone does not enable these things.

If you use a shared network (office, café, university), your IP is shared with many people — the IP alone reveals nothing about you specifically.