AWS Network Load Balancer now supports Listener Rules for custom traffic routing

Network Load Balancer Updates

Network Load Balancer (NLB) now supports listener rules, allowing you to route connections to different target groups based on the source IP address type. This feature enables a single dual-stack NLB to send IPv6 client traffic to IPv6 targets and IPv4 client traffic to IPv4 targets, preserving the original client IP address end to end for both address families.

Previously, serving both IPv4 and IPv6 clients from one NLB meant accepting a tradeoff: either running two separate load balancers (one per IP version) and splitting clients with DNS, or sending all traffic to one target group and losing the original client IP through protocol translation. Listener rules remove that tradeoff by enabling conditional routing at Layer 3, directing each connection to a same-family target group with no translation and no additional infrastructure.

What to do

• Add listener rules to existing dual-stack NLBs without recreating them.
• Rules are supported on TCP, UDP, TCP_UDP, and TLS listeners.
• Rules work alongside existing NLB features including connection draining, target group stickiness, cross-zone load balancing, weighted target groups, and client IP preservation.

Listener rules for Network Load Balancer are available in all AWS commercial Regions and the AWS GovCloud (US) Regions at no additional charge. Standard NLB pricing for load balancer hours and LCUs applies.

Source: AWS release notes

If you need further guidance on AWS, our experts are available at AWS@westloop.io. You may also reach us by submitting the Contact Us form.