Python for network engineer :- Configure multiple router using telnet :-python 2.7

Below script is used to configure multiple devices. In below script ACL needs to be applied to multiple routers. Both Router IP and configuration are stored in different files Make sure when you call a file in python then that file must be stored in same folder where you are storing your python script.

e.g both config.txt must in same folder where you are storing you python program.

Note:- Make sure router IP must be reachable from the machine where python script is configured.

File used in the scripts are :-

Config.txt :- A notepad file contains below ACL configuration

conf t

ip access-list extended Restrict_Outlets

Permit ip any 10.130.127.0 0.0.0.255

deny ip any 10.126.0.0 0.1.255.255

deny ip any 10.128.0.0 0.3.255.255

deny ip any 10.175.0.0 0.0.255.255

deny ip any 10.176.0.0 0.7.255.255

deny ip any 10.190.0.0 0.1.255.255

deny ip any 10.192.0.0 0.15.255.255

deny ip any 10.208.0.0 0.1.255.255

deny ip any 10.210.0.0 0.0.255.255

deny ip any 10.60.0.0 0.0.255.255

permit ip any any

int fa3/0

ip access-group Restrict_Outlets out

no shut

ip.txt :- A notepad file contains below router IP address.

192.168.10.1

192.168.10.2

192.168.10.3

====================Program============

import time

import telnetlib

import sys

#=====Credential for the devices

user = "test"

password = "test"

#=====config.txt contains the ACL

g = open('config.txt', 'r+')   

str = g.read()

g.close

#=====Extracting routers IP from ip.txt file and storing it in variable ips.

ips = [i.strip() for i in open("ip.txt")]

#=====Below FOR loop is  configuring ACL to one router at a time.

for ip in ips:

     telnet = telnetlib.Telnet(ip)

     telnet.read_until("Username: ")

     telnet.write(user + "\n")

     telnet.read_until("Password: ")

     telnet.write(password + "\n")

     telnet.write(str)

     telnet.write("end\n")

     telnet.write("exit\n")

     time.sleep(5)

     print ip

     print telnet.read_all()

====================END============

Router config example:-

hostname R1

interface FastEthernet0/0

 ip address 192.168.10.1 255.255.255.0

 duplex full

 no shut

interface FastEthernet3/0

 no ip address

 ip access-group Restrict_Outlets out ----<<<<<

 shutdown

 duplex auto

 speed auto

line vty 0 4

 login local

line vty 5 16

 login local

!

!

end