COMPUTER NETWORKING

Detailed explanation-1: -Therefore, layer 3 firewalls are able to monitor and filter traffic using the same protocols as routers. They can scan traffic based on Internet Protocol (IP) address, port addresses and similar router-based protocols.

Detailed explanation-2: -A firewall generally works at layer 3 and 4 of the OSI model. Layer 3 is the Network Layer where IP works and Layer 4 is the Transport Layer, where TCP and UDP function. Many firewalls today have advanced up the OSI layers and can even understand Layer 7 – the Application Layer.

Detailed explanation-3: -Static Packet Filter The static packet filtering firewall operates only at the network layer (layer 3) of the OSI model and does not differentiate between application protocols. This type of firewall decides whether to accept or deny individual packets, based on examining fields in the packet’s IP and protocol headers.

Detailed explanation-4: -Layer 3 firewalls filter traffic based on the TCP/IP stack. This approach is sometimes also referred to as packet filtering, because you’re essentially allowing and blocking individual network packets depending on where they originated and which ports they want to talk to.

Detailed explanation-5: -Layer 3 firewalls (i.e. packet filtering firewalls) filter traffic based solely on source/destination IP, port, and protocol. Layer 4 firewalls do the above, plus add the ability to track active network connections, and allow/deny traffic based on the state of those sessions (i.e. stateful packet inspection).