DNS Proximity Routing | NOC.org Support

DNS Proximity Routing directs visitors to the server closest to their geographic location. Instead of sending all traffic to a single origin, NOC's DNS infrastructure identifies where the visitor is located and returns the IP address of the nearest server. This reduces latency, improves load times, and enables regional content delivery strategies.

How Proximity Routing Works

When a visitor queries your domain, NOC's DNS resolvers determine the geographic location of the request based on the source IP of the DNS resolver (typically the visitor's ISP resolver or a public resolver like Google DNS or Cloudflare DNS). NOC then consults your proximity routing configuration to determine which server or endpoint should handle traffic from that region, and returns the corresponding IP address in the DNS response.

The process is entirely transparent to visitors. They receive a normal DNS response containing the IP address of the server best positioned to serve their request. The routing decision happens at the DNS layer, before any HTTP connection is established.

Geographic Routing

Geographic routing lets you map specific regions to specific origin servers or endpoints. You define rules based on geographic criteria:

• Continent-level routing: Send all European visitors to your EU server, all North American visitors to your US server, and all Asia-Pacific visitors to your APAC server.
• Country-level routing: Route visitors from specific countries to designated servers. For example, route Australian visitors to your Sydney server and Japanese visitors to your Tokyo server.
• Region/state-level routing: For large countries, route visitors based on sub-national regions. Send US East Coast visitors to your Virginia data center and West Coast visitors to your Oregon data center.
• Default fallback: Define a default endpoint for visitors whose location does not match any specific rule. This ensures every visitor receives a valid DNS response.

Latency-Based Routing

While geographic routing maps regions to servers based on predefined rules, latency-based routing takes a more dynamic approach. NOC measures the actual network latency between its DNS resolvers and your origin servers, then routes visitors to the endpoint with the lowest measured latency.

Latency-based routing is useful when geographic proximity does not always correlate with network performance. A server that is geographically closer may have higher latency due to network congestion, poor peering, or suboptimal routing. Latency-based routing accounts for these real-world network conditions.

• Continuous measurement: NOC regularly probes your endpoints from multiple locations to maintain current latency data.
• Automatic adaptation: If network conditions change (e.g., a peering link becomes congested), routing adjusts automatically based on updated latency measurements.
• Combined with health checks: Unhealthy endpoints are excluded from latency-based decisions. If the lowest-latency server is down, the next-best option is selected.

Configuration

Proximity routing is configured through the NOC dashboard or REST API:

1. Add your origin server endpoints with their IP addresses and geographic labels (e.g., "US-East", "EU-West", "APAC").
2. Choose your routing mode: geographic (manual region-to-server mapping) or latency-based (automatic lowest-latency selection).
3. For geographic routing, define your routing rules by mapping continents, countries, or regions to specific endpoints.
4. Set a default fallback endpoint for unmatched regions.
5. Configure health checks to ensure unhealthy endpoints are automatically removed from routing decisions.
6. Apply the proximity routing policy to the relevant DNS records.

Use Cases

• Multi-region deployments: Serve visitors from the nearest data center when you have servers deployed across multiple regions (e.g., US, EU, Asia).
• Data residency compliance: Route visitors from specific countries to servers in those countries to comply with data sovereignty requirements (e.g., GDPR, data localization laws).
• Regional content delivery: Serve different content or configurations based on visitor location, such as language-specific sites or region-specific pricing.
• Performance optimization: Ensure that every visitor connects to the lowest-latency server, improving global site speed and Core Web Vitals scores.
• Hybrid cloud deployments: Route traffic to different cloud providers in different regions based on where each provider offers the best performance and pricing.

Proximity Routing vs Smart Routing

Proximity routing and smart routing can be used together. Proximity routing determines which server a visitor should connect to based on location or latency. Smart routing determines whether a server is healthy and available to receive traffic. When combined, you get location-aware routing with automatic failover — visitors are sent to the nearest healthy server, and if that server goes down, traffic automatically shifts to the next nearest healthy endpoint.