IP addresses
layer 3 , network layer .
it may be network layer or transport layer.. it depends on the design of the firewall.. also depends on the requirement specification..
The network layer uses IP addresses to determine whether or not to route a packet from one network to another. Since an IP address has two parts, the network id and the host/client id, this makes it a natural fit (IP addressing) for the network layer.
network layer
The subnet mask is associated with the Network layer of the OSI model, which is the third layer. This layer is responsible for routing packets of data across different networks and determining the best path for them. The subnet mask helps in identifying the network portion of an IP address, which is essential for routing decisions within and between networks.
The network layer is the layer that is responsible for routing packets on the network. This is the layer in which Internet protocol operates. In the seven layer OSI model, the network layer is the third layer from the bottom.
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Network Layer
Physical, Data link and Network layers make the Network Support layers.
A layered network, or a network layer, is the set up of how data is sent over a network. Each layer has it's own responsibility by either capturing the data or routing it to a computer on the network.
The Layer 3(Network Layer) is associated with IP addressing.Because,It converts the frames into packets and address them to send across the other network through intermediary devices.While transferring across the other network's have to know about the destination IP address and also source IP address's deals with IP address.
Network Layer