aws-ecs-service-connect-ipv6

IPv6 DNS issues in AWS ECS Service Connect occur because dual-stack DNS returns IPv6 addresses, but IPv4-only Fargate tasks lack outbound IPv6 routing. This causes connectivity failures when tasks attempt to resolve and reach service aliases.

Fix IPv6 DNS resolution failures in ECS Service Connect by configuring IPv4-only DNS records via Cloud Map, switching to OTLP HTTP, or enforcing IPv4 protocol selection on clients. These steps ensure IPv4-first paths for reliable service communication.

The best way to force IPv4 traffic for ECS Service Connect clients is to enforce IPv4 protocol selection on the client side or introduce IPv4-only DNS records in Cloud Map. This bypasses dual-stack IPv6 alias resolution entirely.

ECS Service Connect does not safely support dual-stack IPv6 aliases for IPv4-only Fargate tasks without mitigation. IPv4-only tasks cannot route outbound traffic to the IPv6 addresses returned by dual-stack DNS, resulting in connection failures.

Switch from gRPC to OTLP HTTP to resolve ECS Service Connect networking issues when dual-stack IPv6 DNS aliases disrupt gRPC protocol selection. Enabling OTLP HTTP provides a practical mitigation path to restore reliable IPv4-first service communication.

The limitations of using ECS Service Connect with IPv6 aliases include connectivity failures for IPv4-only Fargate tasks due to missing outbound IPv6 routing. Production environments require mitigations like IPv4-only Cloud Map records to prevent recurrence.