Python Sockets connect to FTP don't receive what I expect

Question

I am using python socket to connect to ftp.rediris.es and I don't receive the answer I expect after sending data. I explain this better with my code and answers: This is my code (test.py)

#!/usr/bin/env python

import socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

print "Socket Created"

port = 21

host = "ftp.rediris.es"

ip = socket.gethostbyname(host)

print ip

print "ip of " +host+ " is " +ip

s.connect ((ip, port))

print "Socket Connected to "+host+" on ip "+ ip

message = "HELP\r\n"

s.sendall(message)

reply = s.recv(65565)

print reply

This is the answer when I run the code:

 python test.py
Socket Created
130.206.1.5
ip of ftp.rediris.es is 130.206.1.5
Socket Connected to ftp.rediris.es on ip 130.206.1.5
220-  Bienvenido al FTP anónimo de RedIRIS.
220-Welcome to the RedIRIS anonymous FTP server.
220 Only anonymous FTP is allowed here

And this is what I expect:

telnet
telnet> open ftp.rediris.es 21
Trying 130.206.1.5...
Connected to zeppo.rediris.es.
Escape character is '^]'.
220-  Bienvenido al FTP anónimo de RedIRIS.
220-Welcome to the RedIRIS anonymous FTP server.
220 Only anonymous FTP is allowed here
HELP
214-The following SITE commands are recognized
 ALIAS
 CHMOD
 IDLE
 UTIME

I have tried this on the port 80 towards www.google.com, sending a GET / HTTP/1.1\r\n\r\n and seen the header perfectly. What happens¿? Am I not sending the command right to the server¿? Thank you in advance

Answer 1

You may check if the last line of 220 Only anonymous FTP is allowed here has been received before sending the HELP message, something like read_until in telnetlib.

Like this, it works for me:

import socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print "Socket Created"
port = 21
host = "ftp.rediris.es"
ip = socket.gethostbyname(host)

print ip
print "ip of " +host+ " is " +ip

s.connect ((ip, port))
print "Socket Connected to "+host+" on ip "+ ip

reply = ''
while True:
    message = "HELP\r\n"
    reply += s.recv(1024)
    if not reply:
        break
    if '220 Only anonymous FTP is allowed here' in reply:
        s.sendall(message)
        break    
reply += s.recv(65535)
print reply

Printout:

Socket Created
130.206.1.5
ip of ftp.rediris.es is 130.206.1.5
Socket Connected to ftp.rediris.es on ip 130.206.1.5
220-  Bienvenido al FTP anónimo de RedIRIS.
220-Welcome to the RedIRIS anonymous FTP server.
220 Only anonymous FTP is allowed here
214-The following SITE commands are recognized
 ALIAS
 CHMOD
 IDLE
 UTIME
214 Pure-FTPd - http://pureftpd.org/

That said though, not entirely sure why you haven't chosen the more suitable modules like ftplib or telnetlib to begin with.