Task networking in aws Fargate

Hello,

Yes, you can enable the auto-assign public IP for Fargate task.

According to the ECS document [1]， you can optionally assign a public IP address to the task's ENI when using a public subnet. This could be configured during the ECS task creation or ECS service creation. Hence, for troubleshooting the connection issue, there have multiple points you can check:

1) Do you enable the auto-assign public IP during ECS task creation or ECS service creation?

2) Is the Fargate task deployed in the subnet which contain a route to an internet gateway. ? If the subnet already have internet gateway, but didn't contain a route to an internet gateway, please follow this document to configure it [2] (Begin from Step 5). 

3) Confirm the security group that Fargate task use allow the correct IP address and port to access.

4) Confirm the VPC NACL has allow the correct IP address and port to access [3].

5) If the traffic from outside-VPC, make sure you access the task with Fargate task's public IP instead of Fargate task's private IP.

Hope above information helps.

[1] Fargate task networking - https://docs.aws.amazon.com/AmazonECS/latest/userguide/fargate-task-networking.html

[2] Connect to the internet using an internet gateway - Create a custom route table - https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Internet_Gateway.html#Add_IGW_Routing

[3] Control traffic to subnets using Network ACLs - Default network ACL - https://docs.aws.amazon.com/vpc/latest/userguide/vpc-network-acls.html#default-network-acl