Public IPs, Private IPs, and Elastic IPs
~10 min read
Three different IP addresses an instance might have, and why they behave differently across a stop/start cycle.
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Key points
- •Private IP: stable within the VPC for the instance's life, used for internal communication
- •Auto-assigned Public IP: changes on every stop/start — never hardcode or point DNS at this
- •Elastic IP: static, persists across stop/start, can be moved between instances, but costs money while unattached
- •For anything needing a stable public address (e.g. a DNS A record), use an Elastic IP, not the auto-assigned public IP