Routing Policies – IP-based Routing

IP-based Routing is a type of routing policy used to direct client traffic based on the source IP address of the request. This technique is commonly implemented in DNS-based traffic management and application delivery controllers (ADCs) (e.g., AWS Route 53, Azure Traffic Manager, F5, etc.) to serve customized content or direct traffic to specific infrastructure resources.

 The concept of IP-based Routing:

IP-based routing routes user requests to different resources based on the user's IP address or IP range. This is useful when twtech wants to:

• Serve different content or versions of an app to users from different IPs or IP ranges.
• Enforce geographical or organization-based traffic rules.
• Implement network segmentation or tenant-specific behavior in multi-tenant environments.

 Common Use Cases

Use Case	Description
Geo-specific content delivery	Deliver content based on user's IP-based geolocation.
Security enforcement	Restrict access to services based on source IP (e.g., internal corporate networks).
Compliance control	Route traffic from certain IPs through compliant infrastructure (e.g., GDPR, HIPAA).
Performance optimization	Send users from specific IP ranges to the nearest or fastest backend.
Multi-tenant architecture	Route tenants to different environments or backends using their assigned IP ranges.

 How It Works (Example with AWS Route 53)

1. Client sends DNS request to resolve a domain.
2. Route 53 policy inspects the source IP of the request.
3. Rules match IP ranges defined in the routing policy.
4. DNS response points to the target resource (e.g., web server, load balancer) associated with that IP range.

 IP-based Routing vs Other Routing Policies

Routing Policy Type	Description
Simple Routing	One record returned for all queries.
Weighted Routing	Distributes traffic proportionally based on assigned weights.
Latency-based Routing	Routes to the resource with the lowest latency.
Geolocation Routing	Routes based on geographical location.
Geo-proximity Routing	Routes based on location and weight bias.
IP-based Routing	Routes based on specific IP ranges of the client.

 Pros

• Precise control over traffic.
• Supports tenant and user-level customization.
• Helps enforce security and compliance.

 Cons

• Requires management of IP ranges.
• May not adapt well to dynamic IP address changes (e.g., mobile or ISP NATs).
• Complexity increases with scale.

 Security Tip

IP-based routing should be used with other access control mechanisms like WAFs, VPNs, or IAM rules to ensure robust security, as IP addresses can be spoofed in certain environments.