Outbound Gateway for AWS

Sophos UTM on AWS is a solution designed to automatically scale for inbound web application traffic and outbound web content filtering. This solution consists of multiple Sophos UTM on AWS units with several roles (Queen & Worker) which work with AWS services. The solution is designed to work across AWS Availability Zones in a single AWS region, and to work with an Internet-facing Elastic Load Balancer that is used to distribute traffic to Sophos UTM on AWS Workers for traffic scanning. To use the solution you need to subscribe to Sophos UTM on AWS via AWS Marketplace.

OGW (Outbound Gateway) is a setup in AWS where an Auto Scaling group of Sophos UTM on AWS units is load-balanced by gateways. The whole setup, Sophos UTM on AWS plus gateway, is called Outbound Gateway. OGWs act as outbound load balancers.

The OGW deployment serves two main purposes, firstly scaling of Sophos UTM on AWS units to handle increasing outbound traffic loads, and secondly, in some cases, the establishment of a communication path to the Internet for instances that are located within VPCs which lack Internet gateways.

Use cases for the OGW include:

OGW: Concept

The high level architecture of the OGW deployment is shown below. Typical deployment per VPC will consist of three Sophos UTM on AWS instances, one controller where configuration is performed, and two workers (one per Availability Zone). Both controller and workers are contained within Auto Scaling groups, which will launch a replacement Sophos UTM on AWS should one fail, and workers may also scale under high load. In addition to Sophos UTM on AWS units, there are gateway instances which are deployed within each VPC. There is a minimum of two of these per VPC, where they are deployed into separate subnets, and provide High Availability by way of a failover mechanism. To facilitate external traffic routing they connect to Sophos UTM on AWS workers via GRE (Generic Routing Encapsulating) tunnels (established during deployment of the gateways).

Overview

To use the feature you have to deploy Outbound Gateway(s) for AWS in Sophos UTM on AWS. This can be done:

Both methods utilize a CloudFormation template.

Note – You need to decide for a method during object creation. It cannot be changed afterwards.