You know how to find your IP address, right? You can just run ifconfig and it will tell you.  Now the big question: How did your computer get that IP address? It didn’t buy one at the IP store or pull one out of the closet, it had to get it somehow. Well, there’s two places it
could have come from, and in this post we’ll talk about where your IP address came from.

The first choice is called a static assignment. That means your ISP picked an IP from the collection it has and assigned it to you.

Home address

It’s like the address of your house. It isn’t going to change, it’s always going to be that address. Unless you move your house completely, then your house address will change. If you move ISPs, then your IP address would change.

This used to be the way IP addresses were assigned to everyone. Remember how I said we’re running out of IP addresses? That doesn’t work as well any more. Now we have a dynamic pool.

Dead Pool

Not Dead Pool, but a dynamic pool of IP addresses. When you tell your ISP ‘Hey, I’m going online’ it takes an IP address from its pool and assigns it to you. When you turn off your computer or your router, you give that IP address back to the pool.

Swimming Pool

Well, not into the swimming pool but rather the collection of IP addresses.

This is called DHCP, or Dynamic Host Configuration Protocol. That’s quite the mouthful, so we’ll stick with DHCP.

DHCP usually comes with a timer. That means you have to renew your IP address periodically. Normally it just means you say ‘yes, I’m here, I’m still using it, go away’ but depending on how the configuration works, you might get a new IP address. In other words, your IP addresses aren’t set in stone like your house address, but are likely to change. Like if you had a houseboat and moved it often, then that house address would change.