Online experts believe that a static IP or Dedicated IP address can boost search engine ranking. How do I purchase a Dedicated IP for my hosting account? What's a static IP address? An IP address - Internet Protocol address - is a number assigned by your provider that identifies your computer or device when it goes online. It works similarly to a home address or a phone number: when you use the internet, the network uses your IP address so it knows where to send data to.
You need to look at for this. Whilst VPC is free outside of the usual instance pricing, it doesn't work with Micro instances (the cheapest ones). When not using VPC, you're assigned IP addresses through DHCP. When the DHCP lease expires, or you restart, your IP is released back to the pool. VPC lets you use private IP addressing, you can use it with Elastic IPs and is much easier to integrate with a physical infrastructure setup.
If you're only testing/investigating AWS and have little or no budget to use anything other than a Micro instance, I'd just suck it up and deal with the changing of IPs. If you've got a budget that lets you use instances other than Micro, then go for VPC. Also, if you're doing more than testing/investigating I'd recommend starting with VPC straight away as trying to migrate from a non VPC to a VPC infrastructure is a massive PITA. Quote from Amazon: 'By default, all accounts are limited to 5 Elastic IP addresses. If you need more than 5 Elastic IP addresses, we ask that you apply for your limit to be raised. We will ask you to think through your use case and help us understand your need for additional addresses.
You can apply for more Elastic IP addresses here. In order to help ensure our customers are efficiently using the Elastic IP addresses that they have associated with their account, we impose the $.01/hr charge when these IP addresses are not mapped to an instance.'
– Sep 14 '16 at 8:43. Looks like they have configured ARP statically so you can only use the IP address on an instance that was bound to that instance through the EC2 management console. I just configured one of my instances to use a static IP address other than the one assigned through the management console and rebooted the instance. I'm still receiving ARP responses on the old address but not receiving ARP responses on the new address at all. Unfortunately for me, I have a not responding instance (NFS File Server) stuck in a stopping state while I attempt to terminate it. The IP Address bound to that instance cannot be re-assigned to a replacement instance so now I have to reconfigure.