Networking - TCP sockets - multichoice questions

Question 1

For a communication session between a pair of programs, which program is the client and which is the server?

• The program that initializes the TCP connection is the client
• The program that initializes the TCP connection is the server

Question 2

In TCP/IP networking, what parameter is used to specify a particular process on a machine?

• IP address
• window size
• port number
• protocol
• None of the above

Question 3

What file contains a catalog of well known services?

• /etc/services
• /etc/protocols
• /usr/share/net/services
• /usr/share/net/protocols
• None of the above

Question 4

Which port number serves as a boundary between privileged and non-privileged ports?

• 25
• 991
• 1024
• 6000
• 65535

Question 5

If on one machine, elvis was using both the Firefox and Chrome web browsers to access the same website, what parameter would differ for the two involved sockets?

• The client IP Address
• The server port number
• The client port number
• The server IP Address
• None of the above

Question 6

When a socket is opened by a server and awaiting client connections, what state is the socket said to be in?

• Waiting
• Listening
• Established
• Initialized
• None of the above

Use the following transcript to answer the next 4 questions.

[elvis@station elvis]$ netstat -tuna
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address       Foreign Address         State
tcp   0     0   127.0.0.1:32768     0.0.0.0:*               LISTEN
tcp   0     0   0.0.0.0:111         0.0.0.0:*               LISTEN
tcp   0     0   0.0.0.0:6000        0.0.0.0:*               LISTEN
tcp   0     0   0.0.0.0:22          0.0.0.0:*               LISTEN
tcp   0     0   69.57.79.162:53     0.0.0.0:*               LISTEN
tcp   0     0   192.168.0.254:53    0.0.0.0:*               LISTEN
tcp   0     0   127.0.0.1:53        0.0.0.0:*               LISTEN
tcp   0     0   0.0.0.0:631         0.0.0.0:*               LISTEN
tcp   0     0   127.0.0.1:25        0.0.0.0:*               LISTEN
tcp   0     0   127.0.0.1:953       0.0.0.0:*               LISTEN
tcp   0     0   127.0.0.1:6010      0.0.0.0:*               LISTEN
tcp   0     0   127.0.0.1:631       127.0.0.1:32773         ESTABLISHED
tcp   0     48  69.57.79.162:22     66.187.233.200:35954    ESTABLISHED

[elvis@station elvis]$ grep 53 /etc/services
domain      53/tcp          # name-domain server
domain      53/udp           
gdomap      538/tcp         # GNUstep distributed objects
gdomap      538/udp         # GNUstep distributed objects
cfengine    5308/tcp        # CFengine
cfengine    5308/udp        # CFengine
knetd       2053/tcp        # Kerberos de-multiplexor
rndc        953/tcp         # rndc control sockets (BIND 9)
rndc        953/udp         # rndc control sockets (BIND 9)

Question 6

Choose the correct sentence.

• 69.57.79.162 is connected to elvis station over SSH protocol
• 66.187.233.200 is connected to elvis station over SSH protocol
• 69.57.79.162 is connected to elvis station using port 35954
• 66.187.233.200 is connected to elvis station using port 35954
• None of the above

Question 7

How many TCP/IP clients are currently connected to services on elvis machine?

• 1
• 0
• 2
• 11
• None of the above

Question 8

Of these, how many are on remote machines?

• 1
• 0
• 11
• 2
• None of the above

Question 9

The three sockets bound to port 53 most likely belong to what service?

• SSH (Secure Shell)
• HTTP (Hypertext Transfer Protocol)
• FTP (File Transfer Protocol)
• DNS (Domain Name Service)
• TELNET (Telnet Service)

Question 10

Which of the below characteristics are typically associated with a TCP socket?

• The syscall socket(AF_INET, SOCK_DGRAM, 0) creates the socket of type TCP.
• TCP sockets provide reliable, in-order byte-stream transfer between client and server.
• The function call socket(AF_INET, SOCK_STREAM, 0) creates a socket of type TCP.
• The server uses accept() function for incoming client connections.
• Data from multiple clients can be received on the same socket.
• When a server is contacted by a client, it creates a new server-side socket to communicate with that client.

Question 11

In TCP, how does the server know the client IP address and the port number to reply to in response to a received message?

• Using the DNS protocol
• Every message sent by the client contains the IP number and port.
• The accept() syscall creates a new socket that is bound to the specific client, which is established using the IP and port number of the client.
• The server looks for the correct port number in the /etc/services file.

Question 12

In UDP, how does the server know the client IP address and the port number to reply to in response to a received message?

• Using the DNS protocol
• Every message sent by the client contains the IP number and port.
• The accept() syscall creates a new socket that is bound to the specific client, which is established using the IP and port number of the client.
• The server looks for the correct port number in the /etc/services file.

Question 13

A given server has 5 established connections bound to port 80, how many socket files the server holds?

• 5
• 6
• 1
• None of the above