PCPP2 Network Programming Practice Test 2 — 15 Questions

Question 1

In a multi-threaded Python server, why is it discouraged to share a single socket object across multiple threads without synchronization?

Accepted Answer

Concurrent access can lead to interleaved or corrupted data streams.. Socket operations are generally thread-safe in CPython, but overlapping operations on the same file descriptor can lead to interleaved data or corrupted state.

Answer

Python's GIL prevents concurrent socket access.

Answer

Sockets are not picklable.

Answer

The socket module raises a RuntimeError for concurrent usage.

Question 2

What is the purpose of the socket.recvfrom() method?

Accepted Answer

It retrieves data and the sender's address in a single call.. recvfrom() is designed for connectionless protocols like UDP to receive data and return the address of the sender.

Answer

It is for TCP servers to accept new connections.

Answer

It forces a socket to switch to UDP mode.

Answer

It is used to receive large files in chunks.

Question 3

Why is the socket.socket() constructor typically called with socket.AF_INET and socket.SOCK_STREAM for a standard web server?

Accepted Answer

To provide a reliable, connection-oriented byte stream.. AF_INET defines IPv4 and SOCK_STREAM defines the TCP protocol, which are standard for HTTP.

Answer

To enable UDP broadcast.

Answer

To reduce latency for real-time video.

Answer

To support raw IP packet injection.

Question 4

Which of the following is the correct way to close a socket object in Python?

Accepted Answer

socket.close(). The close() method should be called on the socket object to release the underlying file descriptor.

Answer

socket.destroy()

Answer

socket.shutdown()

Answer

del socket

Question 5

What is the significance of the SO_BROADCAST option in a UDP socket?

Accepted Answer

It enables the socket to send packets to a broadcast address.. SO_BROADCAST is a prerequisite for sending packets to the broadcast address on a network interface.

Answer

It allows the socket to handle incoming multicast traffic.

Answer

It allows the socket to listen to all ports on a machine.

Answer

It makes the socket connection-oriented.

Question 6

When using select.select(inputs, outputs, exceptions), what does the 'outputs' list signify?

Accepted Answer

Sockets that are ready to send data without blocking.. The 'outputs' list contains sockets that are monitored for readiness to accept data for writing without blocking.

Answer

Sockets that are closed for writing.

Answer

Sockets that have finished writing.

Answer

Sockets that have received an interrupt signal.

Question 7

Which of the following describes the behavior of TCP_NODELAY?

Accepted Answer

It disables Nagle's algorithm for low-latency communication.. TCP_NODELAY disables Nagle's algorithm, which otherwise buffers small packets to send them as one, reducing network overhead but increasing latency.

Answer

It forces the socket to ignore packet loss.

Answer

It enables UDP-like performance for TCP.

Answer

It increases the packet size to match MTU.

Question 8

You are configuring a socket timeout. What happens if you call socket.settimeout(5.0) and the operation exceeds 5 seconds?

Accepted Answer

A socket.timeout exception is raised.. A timeout sets a limit on blocking operations; if the time is exceeded, a socket.timeout exception is raised.

Answer

The socket automatically closes.

Answer

The operation returns None.

Answer

The kernel silently drops the connection.

Question 9

Which THREE of the following are valid address families or socket types used with the Python socket module?

Accepted Answer

socket.AF_INET. AF_INET and AF_INET6 are common address families, while SOCK_STREAM and SOCK_DGRAM are standard socket types.

Answer

socket.AF_TCP

Answer

socket.SOCK_LOCAL

Question 10

Which TWO of the following methods are typically used on a TCP server socket?

Accepted Answer

socket.listen(). A TCP server uses bind() to assign the address and listen() to prepare for incoming connections.

Answer

socket.sendall()

Answer

socket.recvfrom()

Answer

socket.connect()

Question 11

Which TWO of the following are differences between TCP and UDP?

Accepted Answer

TCP has higher overhead than UDP.. TCP is reliable and connection-oriented, whereas UDP is connectionless and unreliable.

Answer

UDP is connection-oriented.

Answer

UDP is always faster than TCP in every network condition.

Answer

TCP supports multicasting natively.

Question 12

Which THREE of the following are valid ways to send or receive data?

Accepted Answer

socket.send(). recv(), send(), and sendall() are the primary methods for data transfer in Python sockets.

Answer

socket.transfer()

Answer

socket.push()

Question 13

Which TWO of the following are true regarding the socket.shutdown() method?

Accepted Answer

It can be used to disable only the receiving side of the socket.. shutdown() can disable reading, writing, or both, which is useful for protocol-level signaling.

Answer

It is identical to the close() method.

Answer

It causes an immediate memory deallocation of the socket object.

Answer

It automatically reopens the socket if called twice.

Question 14

Which THREE of the following are true regarding the use of the socket module in Python?

Accepted Answer

Sockets are identified by file descriptors in the OS.. Sockets are file descriptors, they can be set to non-blocking mode, and they must be closed to avoid resource leaks.

Answer

The send() method is guaranteed to send the entire buffer requested.

Answer

Closing a socket does not terminate the underlying file descriptor.

Question 15

Which THREE of the following options can be used with socket.setsockopt()?

Accepted Answer

socket.SO_KEEPALIVE. SO_REUSEADDR, SO_KEEPALIVE, and TCP_NODELAY are standard options supported by most systems.

Answer

socket.TCP_BUFFER_SIZE

Answer

socket.SO_MAX_CONNECTIONS