Belier: Script Your SSH Connection

Introduction link

Belier¹ allows opening a shell or executing a command on a remote computer through an SSH connection. The main feature of Belier is its ability to cross several intermediate computers before completing the job.

• Belier reaches the final computer through intermediate machines.
• You can execute commands with any account available on the remote computer.
• It is possible to switch accounts on intermediate computers before accessing the final computer.
• You can open a data tunnel through every host you cross to the final host.
• Belier generates one script for each final computer to reach.

Belier aims to give a single system administrator a tool to work independently, without requiring modification of the computers they need to cross, just using the current configurations of every machine they have to work with. So it’s not a revolutionary tool, but it helps to be productive quickly.

For instance, here is what is possible to do with it:

²

Installation link

To install it, as usual it’s easy on Debian:

  aptitude install belier
  

Configuration link

The configuration is really simple. Type line by line in a ‘connection’ file, connection information for:

1. The server name or IP
2. The username
3. The password

It should look like this:

  server1_bound username password
server2_bound username password
server3_bound username password
final_server username password
  

Then generate an automatic shell connection script with Belier:

  bel -e ~/connection
  

You should now have a script containing all the commands to quickly connect to your desired server:

  #!/usr/bin/expect -f
set timeout 10

spawn ssh -o NoHostAuthenticationForLocalhost=yes -o StrictHostKeyChecking=no  server1_bound
expect -re  "(%|#|\$) $"
send -- "su - username\r"
expect ":"
send -- "password\r"
expect -re  "(%|#|\$) $"
send -- "ssh -o NoHostAuthenticationForLocalhost=yes -o StrictHostKeyChecking=no  server2_bound\r"
expect -re  "(%|#|\$) $"
send -- "su - username\r"
expect ":"
send -- "password\r"
expect -re  "(%|#|\$) $"
send -- "ssh -o NoHostAuthenticationForLocalhost=yes -o StrictHostKeyChecking=no  server3_bound\r"
expect -re  "(%|#|\$) $"
send -- "su - username\r"
expect ":"
send -- "password\r"
expect -re  "(%|#|\$) $"
send -- "ssh -o NoHostAuthenticationForLocalhost=yes -o StrictHostKeyChecking=no  final_server\r"
expect -re  "(%|#|\$) $"
send -- "su - username\r"
expect ":"
send -- "password\r"
expect -re  "(%|#|\$) $"
interact +++ return
  

You can now launch the command with final_server.sh :-)