import telnetlib
import time


#Open telnet connection to devices

def open_telnet_conn(ip):
    try:
        username = 'jtavares'
        password = 'teste'


        port = 23
        #Specify the connection timeout in seconds for blocking operations
        connection_timeout = 5
        reading_timeout = 5
        #Loggin into device
        connection = telnetlib.Telnet(ip,port, connection_timeout)

        #Waiting to be asked for a username
        router_output = connection.read_until("Username:", reading_timeout)
        #Enter the username
        connection.write(username + "\n")
        time.sleep(1)

        #Waiting to be asked the password
        router_output = connection.read_until("Password:", reading_timeout)
        #Enter the password when asked
        connection.write(password + "\n")

        #Sends a command to the routter
        connection.write("terminal length 0\n")
        connection.write("show running 0\n")
        router_output = connection.read_very_eager()
        print (router_output)


        #Closing the connection
        connection.close()

    except IOError:
        print "Input parameter error!"

 open_telnet_conn("128.8.4.100")