I just mentioned that VMs can have internal and external IP addresses. Let's explore this in the GCP console. So I'm going to go ahead here and try to create a VM, and I'm just going to leave all these as the default, but want to focus on is the networking interface. So I'm going to expand this menu right here, and click on Networking. So here we see that this is currently being created in the default network. We see the exempt subnetwork, and that matches the region that I've chosen, which I just left to the default. Specifically we see that this has a slash 20 mask here, and that really allows for live addresses, actually 4,096 addresses to be exact, and four of those you can't use. So you'll be able to create over 4,000 VM instances in this subnet. So let me go ahead now. If I focus on the primary internal IP, you can see this by default ephemeral, I could also custom input an internal IP address or I could actually reserve one. Meaning that if I restart it and stop this VM, it still have the same IP. The same goes for the external IP. Moreover here, I actually don't even need an external IP. So as I just mentioned, only internal IPs are required for VM instances. I could actually say that I don't want an external IP address altogether. But let's leave that for now and let me just create this instance to show the internal and external IP addresses that get generated. So here we are. The instance has been created. You can see I have the internal IP address and that is within that subnet masks that we just looked at, and I also have the external IP address. Now, I want to prove to you this external IP address is ephemeral. The way I'm going to do that is I'm just going to click on this instance. I'm going to stop it. So here we can see that the instance has now been stopped. The internal IP address is actually still here, but the external IP address is gone. If I now go ahead and restart that, it's going to ask me if I'm sure I want to do that because I get build for that. Yes, I do want to restart this instance. We're not going to wait for that instance to start backup, and here we go. The instance is starting, but we can already see that the external IP address is now different. So this demonstrate that every VM needs an internal IP address. But external IP addresses are optional, and by default they are ephemeral.
