If you've ever noticed your home IP address is different from yesterday, it's because most internet connections use a dynamic IP address. Some servers and services, on the other hand, use a static IP that never changes. What's the difference, and which one do you actually need?
What is a dynamic IP address?
With a dynamic IP, your ISP temporarily assigns your connection an address from a shared pool. That address can change after restarting your router, when its lease time expires, or sometimes for no obvious reason at all. Nearly all home and mobile connections are dynamic by default, since it's far more efficient for an ISP managing a limited pool of addresses.
What is a static IP address?
With a static IP, a specific address is permanently assigned to a connection or server and doesn't change unless it's manually reconfigured. This type usually has to be purchased separately from an ISP or hosting provider, and it's essential for anything that needs a reliable, permanent address.
Quick comparison
| Feature | Dynamic IP | Static IP |
|---|---|---|
| Cost | Usually free (default) | Usually an extra cost |
| Stability | May change | Always stays the same |
| Best for | Regular home and mobile users | Servers, DNS, remote security cameras |
| Privacy | Slightly harder to track long-term | Easier to track long-term |
Which one do you need?
For regular browsing, a dynamic IP is perfectly fine and arguably a bit better for privacy. But if you're running a server that always needs to be reachable at the same address — a web server, a mail server, or a security camera you access remotely — you need a static IP.
How do I know if mine is static or dynamic?
The simplest way is to check your current IP address on Show-IP.ir and compare it a few days later — if it's changed, your IP is dynamic. For a definitive answer, you can also contact your ISP's support.
Key takeaways
- A dynamic IP is temporary and may change periodically — the default for most home connections.
- A static IP never changes and is typically required for servers and always-on services.
- For everyday use, a static IP usually isn't necessary.
- You can check your current IP address right now on the homepage.