Dual-homed firewalls can be compromised if the operating system does not have packet forwarding or routing disabled.
A protocol is a set of rules that dictates how computers communicate over networks.
The application layer, layer 7, has services and protocols required by the user’s applications for networking functionality.
The presentation layer, layer 6, formats data into a standardized format and deals with the syntax of the data, not the meaning.
Routers work at the network layer, layer 3.
The session layer, layer 5, sets up, maintains, and breaks down the dialog (session) between two applications. It controls the dialog organization and synchronization.
The transport layer, layer 4, provides end-to-end transmissions.
The network layer, ...