The egress filter for AWS Application Mesh is set to 'DROP_ALL' by default. This setting can be changed, however by allowing egress traffic through the mesh, workloads will be open to communication with external sources. It is recommended to leave the default setting in place. For more information, see the AWS documentation.
References:
https://docs.aws.amazon.com/app-mesh/latest/APIReference/API_EgressFilter.html
In AWS Console -
In Terraform -
References:
https://docs.aws.amazon.com/app-mesh/latest/userguide/meshes.html
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/appmesh_mesh