Based on the below log, which of the following sentences are true? Mar 1, 2016, 7:33:28 AM 10.240.250.23 - 54373 10.249.253.15 - 22 tcp_ip

The log entry shows a TCP/IP connection. The destination port is 22, which is the well-known port assigned by the Internet Assigned Numbers Authority (IANA) for the Secure Shell (SSH) protocol. In a typical client-server TCP connection, the client initiates the connection from a high-numbered, ephemeral source port (in this case, 54373) to the server's well-known service port (22). Therefore, the machine with the IP address 10.240.250.23 is the client, and the machine with the IP address 10.249.253.15 is the server running the SSH service.

A. The application is incorrect. Port 22 is for SSH, not FTP, which typically uses ports 20 and 21.

B. The client and server roles are reversed. The connection is initiated to the well-known port 22, making 10.249.253.15 the server.

C. This is false. While the SSH payload is encrypted, the TCP/IP packet headers containing source/destination IPs and ports are not, allowing for identification of the client and server.

1. Internet Assigned Numbers Authority (IANA). (2024). Service Name and Transport Protocol Port Number Registry. IANA. Retrieved from https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml.

Reference Detail: The registry explicitly lists "ssh" assigned to port 22 for both TCP and UDP. This confirms the application is SSH.

2. Ylonen

T.

& Lonvick

C. (2006). RFC 4251: The Secure Shell (SSH) Protocol Architecture. Internet Engineering Task Force (IETF).

Reference Detail: Section 4.1

"Use of TCP/IP

" states

"The SSH server normally listens for connections on port 22." This officially documents the server-side port for SSH.

3. Kurose

J. F.

& Ross

K. W. (2017). Computer Networking: A Top-Down Approach (7th ed.). Pearson.

Reference Detail: Chapter 2

Section 2.7

"Socket Programming with TCP

" explains the client-server model. The server has a welcoming socket on a well-known port

while the client's operating system assigns an ephemeral port number to the client's socket for the specific connection. This principle identifies 10.240.250.23 (source port 54373) as the client and 10.249.253.15 (destination port 22) as the server.