Which of the following is NOT a characteristic or shortcoming of packet filtering gateways?

Packet filtering firewalls use routers with packet filtering rules to grant or deny access based on source address, destination address, and port.

They offer minimum security but at a very low cost, and can be an appropriate choice for a low-risk environment.

Source: TIPTON, Harold F. & KRAUSE, Micki, Information Security Management Handbook, 4th edition (volume 1), 2000, CRC Press, Chapter 3, Secured Connections to External Networks (page 60).