A smart rule, on the other hand, knows that returning packets will head in the opposite direction and so does not require the second rule. Next are some of the pros and cons for this type of firewall. Pros Offers improved security over basic packet filters due to packet examination. Offers a degree of application independence, based on level of stateful packet examination. Better logging of activities over basic packet filters.
Configuration changes to the protected workstations are unnecessary.
They allow a direct connection between endpoints through the firewall. No hiding of your private systems. Potential for vulnerability to be exploited. Setting up stateful packet examination rules is more complicated. Only supported protocols at the application layer.