ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Script to login to multiple Cisco devices with Telnet & SSH using Expect

Updated on August 2, 2010

SSH login into multiple devices made easy!

You have a list of devices on SSH access that you want to login and execute a specific command, and your simple looped script is just not working because of the RSA fingerprint.

The authenticity of host 'xx.yy.zz.aa (xx.yy.zz.aa)' can't be established.
RSA key fingerprint is 7f:17:e5:b9:c2:99:10:ac:9c:8b:d5:5c:2e:4c:b4:d5.
Are you sure you want to continue connecting (yes/no)?

What do you do next?

Use the EXPECT!

EXPECT is a program that "talks" to other interactive programs according to a script.

EXPECT is a toolkit for automating interactive programs, such as TELNET, SSH and FTP. You can write and execute SSH or TELNET logon scripts and do whatever you wish using a script file from a Bastion host.

EXPECT reads commands from a script file, spawns a process like SSH or TELNET, sends text from the script file to the SSH process, saves every character returned from the SSH session, and “looks” for known character strings that the user “expected”. The script can test for different strings and execute different code based on the results.

Connecting to my switch manually
Connecting to my switch manually

#!/usr/bin/expect -f
#! /bin/bash

set force_conservative 0 ;# set to 1 to force conservative mode even if
;# script wasn't run conservatively originally
if {$force_conservative} {
set send_slow {1 .1}
proc send {ignore arg} {
sleep .1
exp_send -s -- $arg }
set timeout 3000
log_user 1
set var1 [lindex $argv 0 ]
set var2 [lindex $argv 1]
puts $var1
puts $var2
spawn telnet $var1
expect "Username: "
send -- "KrisPrem\r"
expect "*assword: "
send -- "mypassword\r"
log_user 1
expect "*>"
send "en\r"
expect "*assword: "
send -- "myenablepassword\r"

expect "$var2"
send-- "show clock\r"

send -- "exit\r"


automatically logged in and executed a command
automatically logged in and executed a command

In the script above, i've used variable var1 to save the IP address and variable var2 for special purpose.

In a router running IOS, when you are in global configuration mode you know the prompt would be # so, basically you could expect it to be # and use expect "# " in the script followed by send appropriate commands you wish to.

Hope this hub was helpful.


What's Next


I'm not so good at explaining thing. If you need more details on the above script let me know....

Anyway, I'll create a hubpage on automation for Cisco routers and Switches based on expect and nmap.


    0 of 8192 characters used
    Post Comment

    No comments yet.


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

    Show Details
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)