What configuration is necessary to allow the virtual security appliance to route the traffic?

Explanations:

Disabling network ACLs is not a necessary step and could compromise security by allowing all traffic, which goes against best practices. Network ACLs can be configured to work alongside the virtual security appliance without needing to disable them.

Configuring the security appliance’s elastic network interface for promiscuous mode is typically used for monitoring traffic rather than routing it. The appliance should function correctly without requiring promiscuous mode, as it needs to process traffic based on its routing capabilities.

Disabling the Network Source/Destination check on the security appliance’s elastic network interface is essential for allowing the appliance to route traffic. This setting permits the appliance to receive traffic that is not addressed to it directly, which is critical in inline deployments.

Placing the security appliance in a public subnet with an internet gateway is unnecessary for routing traffic. The placement of the appliance depends on the network architecture and security policies. It can be in a private subnet while still being able to route traffic if configured correctly.