Why do we call packet filter firewalls .... packet filter firewalls?
A firewall operating as a packet filter passes or blocks traffic to specific addresses based on the type of application. The packet filter doesn’t analyze the data of a packet; it decides whether to pass it based on the packet’s addressing information. For instance, a packet filter may allow web traffic on port 80 and block Telnet traffic on port 23. This type of filtering is included in many routers. If a received packet request asks for a port that isn’t authorized, the filter may reject the request or simply ignore it.
I was always told and taught that ports belong to the Transport Layer, which is Layer 4, and what's in L4 is called a segment not a packet. Why do they call it packet firewall?