IP Addresses
Definition
IP Addresses are unique numerical identifiers assigned to devices on a network, enabling seamless communication and data exchange between them.
Use Cases
- Netflix: Running internet-facing services on AWS while controlling outbound traffic identity for allowlists and partner integrations — Uses AWS VPC networking with public and private subnets; assigns public IPs to edge-facing components and uses fixed egress IP patterns (commonly via NAT and allocated public IPs such as Elastic IPs) so external partners can allowlist known source addresses (Improved reliability of partner connectivity and simplified security allowlisting by keeping predictable internet-facing and outbound IP identities)
- Cloudflare: Providing a global CDN and DDoS protection service that customers can point their DNS records to — Operates large anycast IP address ranges announced from many locations; customer domains resolve to Cloudflare IPs so traffic is routed to the nearest edge data center (Lower latency and improved availability for customer websites by routing users to nearby edge locations and absorbing attacks at the edge)
- GitHub: Allowlisting GitHub Actions and webhook traffic to enterprise networks — Publishes documented IP address ranges used by GitHub services so enterprises can configure firewall rules and allowlists; customers use these IP ranges to permit inbound/outbound connectivity (Reduced connectivity failures for CI/CD and integrations by enabling predictable firewall configuration)
Provider Equivalents
- AWS: Amazon VPC (IP addressing) and Elastic IP addresses
- Azure: Azure Virtual Network (IP addressing) and Public IP addresses
- GCP: Google Cloud VPC (IP addressing) and External IP addresses (static/ephemeral)
- OCI: OCI Virtual Cloud Network (VCN) and Reserved Public IP
Frequently Asked Questions
- What's the difference between an IP address and a DNS name?
- An IP address is the numeric network location (like 203.0.113.10). DNS is the naming system that maps a human-friendly name (like example.com) to an IP address. DNS can change the IP behind a name without users noticing, while the IP address is what devices actually use to route traffic.
- When should I use a static IP address vs a dynamic IP address?
- Use a static IP when something must always be reachable at the same address (for example, a public-facing API endpoint, a VPN gateway, or when a partner requires IP allowlisting). Use a dynamic IP for typical client devices or short-lived cloud resources where the address can change without breaking anything, especially when you rely on DNS or load balancers.
- How much do IP addresses cost in the cloud?
- Private IP addresses inside a virtual network are typically included with the resource. Public static IPs often have charges, especially if they are reserved but not attached to a running resource, or if you allocate more than you actively use. Costs vary by provider and region and may also depend on whether the IP is IPv4 (often scarcer and more likely to be charged) versus IPv6.
Category: networking
Difficulty: basic
Related Terms
See Also