Tuesday, 27 December 2011

Linux network - Install ssh in Ubuntu server screenshots



ssh is a remote protocol used in Linux and Unix system. ssh stands for secure shell, which means it provides an encrypted data transfer between a client and server. This is an improvement to the old remote protocol such as rlogin, telnet and ftp. In Ubuntu, ssh package can be found in three initial packages, which are:

openssh-server - contains ssh, scp and sftp server.
openssh-client contains ssh, scp and sftp clients.
metapackage - a portable ssh server and ssh client package.

This is a guide on how to install ssh package in Ubuntu server 8.10 for beginner. First, you have to check whether ssh package has been installed in your Ubuntu server system. We can use dpkg command to list installation package like the screenshot below:

We are going to install ssh package in Ubuntu server through the Internet using apt package management system. So you need to check whether apt package has been install in your ubuntu server or not:




Install ssh package with apt-get command syntax(format) is sudo apt-get install ssh. When apt-get have the package and ready to install, it will prompt us for confirmation. Answer yes to continue, or no if you prefer other ssh package. Here is the screenshot:

The ssh package installation is in progress:

The ssh package installation is finish:

We can check ssh package installation once again with dpkg command to verify:

Check whether ssh daemon (service) is running with ps command like the screenshot example below. If there is no ssh daemon running, you can start ssh with sudo /etc/init.d/ssh start command.

When ssh daemon is running, you can try ssh to your Ubuntu server from client. Below are screenshot examples of accessing ssh server.

Accessing Ubuntu server using ssh from Slackware Linux command line terminal:
luzar@slackware:~$ ssh -l 192.168.0.47
usage: ssh [-1246AaCfgKkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]
           [-D [bind_address:]port] [-e escape_char] [-F configfile]
           [-i identity_file] [-L [bind_address:]port:host:hostport]
           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]
           [-R [bind_address:]port:host:hostport] [-S ctl_path]
           [-w local_tun[:remote_tun]] [user@]hostname [command]
luzar@slackware:~$ ssh -l luzar 192.168.0.47
luzar@192.168.0.47's password:
Linux ubuntu 2.6.27-14-server #1 SMP Wed Apr 15 19:44:38 UTC 2009 i686

The programs included with the Ubuntu system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.

To access official Ubuntu documentation, please visit:
http://help.ubuntu.com/
Last login: Wed Jun 24 04:49:59 2009 from 192.168.0.133
luzar@ubuntu:~$

The first ssh command in the example above shows ssh usage help message. This happens if we enter the wrong ssh syntax. When we get the command right such as in the second ssh command example, we'll be prompted for the user account password. Enter correct user account password and we'll gain access into the Ubuntu server.

We can also access Ubuntu server from Windows operating system using ssh by the help of a program called Putty. You'll find this kind of warning when you first connecting into ssh server.

This is an example screenshot of successful login into your ssh server:

That's all. Remember that ssh is a better choice if you are going to connect remotely to your server. Use it wisely. Good luck.

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