Question

which firewall feature is used to ensure that packets coming into a network are legitimate responses to requests initiated from internal hosts?
application filtering
stateful packet inspection
packet filtering
url filtering

Explanation:

• Application filtering focuses on specific applications and their traffic.
• Stateful packet inspection (SPI) keeps track of the state of network connections (such as TCP streams, UDP sessions). It ensures that incoming packets are part of an existing, legitimate connection initiated from the internal network.
• Packet filtering (basic) just looks at individual packet headers (like source/destination IP, port) without considering the connection state.
• URL filtering is about blocking or allowing access to specific websites based on their URLs.

Answer:

Stateful packet inspection