Socket Creation and Basic Configuration

Question 1

constructor of socket library

Answer 1

socket(family, type, proto, fileno)

Question 2

What does the family field specify?

Answer 2

address family, which format is used to identify the socket address

AF_INET: address family _ internet ==> for ipv4

socket address is (host, port)
host could be hostname or ipv4

hostname first result of DNS resolution is used

Question 3

IPv6 Internet protocols

Answer 3

AF_INET6

Question 4

designed for efficient communication between processes in the same
UNIX machine

Answer 4

AF_UNIX

Question 5

low-level raw packet that communicates with device drivers, i.e., at
the Data Link layer (TCP/IP Layer 2)

Answer 5

AF_PACKET

Question 6

for communication using several Bluetooth protocols.

Answer 6

AF_BLUETOOTH

Question 7

Reliable Datagram Socket (RDS) protocol. (Connectionless reliable
low-latency protocol)

Answer 7

AF_RDS

Question 8

Controller Area Network Automotive bus protocol (developed by
Volkswagen for Linux)

Answer 8

AF_CAN

Question 9

What does the type argument define

Answer 9

the type of the stream, how the socket stream will be handled

type of the transport layer protocol

Question 10

TCP Protocol: Provides connection based, reliable and
sequenced communication

Answer 10

SOCK_STREAM

Question 11

UDP Protocol: Provides datagram based (connectionless),
unreliable and non-sequenced communication

Answer 11

SOCK_DGRAM

Question 12

Allows for customized lower-level programming2

Answer 12

SOCK_RAW

Question 13

Datagram based, reliable and non-sequenced communication

Answer 13

SOCK_RDM

Question 14

Datagram based, reliable and sequenced communication

Answer 14

SOCK_SEQPACKET

Question 15

socket(AF_INET,RAW_SOCKET,…)
vs.
socket(AF_PACKET,RAW_SOCKET,…)

Answer 15

allows you to program at the IP layer

allows you to program at the Data Link layer.

Question 16

what does proto = 0 indicate

Answer 16

underlying Layer 3 protocol. For the vast majority of applications, it is set to 0 which
indicates using the IP protocol.

Question 17

when do we benefit from the fileno argument

Answer 17

This can be useful to close a
detached socket, and in some operations in the non-blocking mode.

Question 18

s = socket() which will create

Answer 18

Pv4 TCP socket.

Question 19

The address family, stream type and protocol are defined aaaaas?

Answer 19

attributes
s.family
s.proto
s.type

Once a socket is created, you cannot set/change the above three attributes, because they
are defined as read-only attributes.

Question 20

You can get a list of all object
attributes and methods using the command

Answer 20

dir(<socket_object>)</socket_object>

Question 21

does the __dict__ attribute exist? why?

Answer 21

no, none of the attributes are writable

Question 22

because every class in Python extends the basic object class, the basic attributes
are also applicable like:

Answer 22

__module__
__class__

Question 23

To verify socket creation, if s is a socket object type the command

Answer 23

type(s)

Question 24

a socket is no
more than a file created by the OS, and a socket descriptor is treated just like any other
file descriptor

Answer 24

UNIX, Windows behaves a bit differently

Question 25

A file descriptor assigned to a socket is always

Answer 25

a positive integer, other than 0 (reserved for stdin), 1 (reserved for stdout) and 2 (reserved for stderr).

Question 26

When communicating over the network using sockets, the ?????? will create the transport, network, and data link packet headers for you

Answer 26

for non raw packets OS However, the programmer is responsible for preparing the application-layer payloads.

Question 27

Closing a socket will deallocate all the resources given to the socket. The file descriptor will also be deallocated, and a value of ??????? is assigned. Once a socket is closed, then all socket operations become illegal.

Answer 27

-1

Question 28

if you do not need the socket anymore, but you need the file descriptor associated with it, then the method????? should be used.

Answer 28

detach

Question 29

If you need to copy the socket specifications, then the method can be used. This will create another socket with the same specifications but with a different file descriptor. These two sockets are distinct sockets, and their operations are independent of each other

Answer 29

dup() not copy, deepcopy or = DIFFERENT FILE DESCRIPTOR if you want same FD, you'll need to use the fileno argument