Basical TCP/UDP client-server problem

Basical TCP/UDP client-server problem - Printable Version

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Basical TCP/UDP client-server problem - maolow - Feb-01-2017

Hi guys!
For an exam I have to code two simple client-server scripts in Python in order to study sockets and transport level protocols.
While they are runnin I have to run Wireshark and sniff the traffic, to study the segments

Basically, this is the code of the UDP part. It works and the message is received, but when I sniff the data, the segment isn't there and there's another port, why?

Client:

import socket
HOST = "127.0.0.1"
PORT = 33333
MSG = 'Prova protocollo UDP'
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.sendto(MSG.encode('utf-8'), (HOST, PORT))

Server:

import socket
PORT = 33333
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind(("", PORT))
print ("Attesa sulla porta: ", PORT)
while 1:
data, addr = s.recvfrom(1024)
print (data.decode('utf-8'))

--------------

The same for TCP:

Client:

import socket

HOST = '' 
PORT = 36000
MSGRCVD = 'Messaggio ricevuto'

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind((HOST, PORT))
s.listen(1)
conn, addr = s.accept()
with conn:
print ('Connesso a: ', addr)
while 1:
data = conn.recv(1024)
print(data.decode())
if not data: break
conn.sendall(MSGRCVD.encode())

Server:

import socket

HOST = "127.0.0.1"
PORT = 36000
MSG = 'Prova protocollo TCP'

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.connect((HOST, PORT))
s.send(MSG.encode())
data = s.recv(1024)
print("Ricevuto: ", data.decode())

RE: Basical TCP/UDP client-server problem - Skaperen - Feb-03-2017

what other port are you seeing? maybe there is other traffic going on at the same time.

RE: Basical TCP/UDP client-server problem - wavic - Feb-03-2017

At TCP when you say a client, the code is for server and server part holds the client code Cool

RE: Basical TCP/UDP client-server problem - Skaperen - Feb-04-2017

yeah, it does look like client and server are reversed under tcp.