SSH and telnet to localhost using python

Question

I am new to python and if the question is very nooby i apologize. Simply put i need to write a script that connects to remote via ssh then telnets to localhost and execute a command on a shell there.

I am using Python 2.4.3. I have read alot of similar questions here , and alot of people suggest to use modules such as Paramiko, Pexpect etc. However this is out of question - i am supposed to use only "native" 2.4.3 libraries. I have tried messing around with subprocess module and i have managed to connect to remote shell (however i need to provide a password - and i would like to avoid that by providing a password in script for example) - but still i need to do a telnet to localhost and execute few commands on a different shell.

Could someone be so kind and give me some hints? Thanks in advance.

TL;DR I am looking for python alternative to this bash command :

./sshpass -p password ssh username@$ip -t "(sleep 1;echo "command" ; sleep 1) | telnet localhost $port;exit;bash" >> testing.txt

What are you actually trying to accomplish? If you are logged in over ssh it makes no sense to telnet localhost -- it just adds an insecure local second connection. — tripleee
– tripleee, Commented Feb 3, 2015 at 9:36
It is for my programming course on my technical university. Basically we have fedora installed on a server with various networking devices connected via localhost to it. What we need to do is to log to the server then connect to these devices, execute a command on their custom shells and save an output to a file on our desktops. We did a same thing in bash 2 weeks ago - and thats how we did it.Now we need to do the same but with python. — sztyrymytyry
– sztyrymytyry, Commented Feb 3, 2015 at 9:44
Are you required to use Python inside the ssh connection? That makes no sense really. Once you are in, you are in a shell. — tripleee
– tripleee, Commented Feb 3, 2015 at 9:48
But with ssh port forwarding you could expose the ports and connect to those using native socket calls. Is that what you want? — tripleee
– tripleee, Commented Feb 3, 2015 at 9:51
What we are supposed to do is to write a script in python that connects to a device,execute a command and save the output to a file. This device is connected as localhost with given port to a remote server with Fedora with given ip. I am sorry , i am only a second year student so please forgive my ignorance - not sure what you mean. With bash it was fairly simple because i used commands like this : ./sshpass -p password ssh username@$ip -t "(sleep 1;echo "command" ; sleep 1) | telnet localhost $port;exit;bash" >> testing.txt - i would like to do something similar in python. — sztyrymytyry
– sztyrymytyry, Commented Feb 3, 2015 at 9:55

Urban48 · Accepted Answer · 2015-02-03 09:56:24Z

2

after a simple search:

telnet: link

import getpass
import sys
import telnetlib

HOST = "hostname"

user = raw_input("Enter your remote account: ")

password = getpass.getpass()

tn = telnetlib.Telnet(HOST)

tn.read_until("login: ")

tn.write(user + "\n")

if password:
    tn.read_until("Password: ")
    tn.write(password + "\n")

tn.write("ls\n")

tn.write("exit\n")

print tn.read_all()

ssh: link

import pxssh
import getpass
try:                                                            
    s = pxssh.pxssh()
    hostname = raw_input('hostname: ')
    username = raw_input('username: ')
    password = getpass.getpass('password: ')
    s.login (hostname, username, password)
    s.sendline ('uptime')   # run a command
    s.prompt()             # match the prompt
    print s.before          # print everything before the prompt.
    s.sendline ('ls -l')
    s.prompt()
    print s.before
    s.sendline ('df')
    s.prompt()
    print s.before
    s.logout()
except pxssh.ExceptionPxssh, e:
    print "pxssh failed on login."
    print str(e)

answered Feb 3, 2015 at 9:56

Urban48

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2 Comments

sztyrymytyry Over a year ago

Damn , there is no pxssh on my machine and i am not supposed to use any other modules besides what i have :S Is there a way to connect via ssh with subprocess and provide a password also ?

Urban48 Over a year ago

@sztyrymytyry you can try supplying the password to stdin

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