SSH Remote Access

1. SSH Client Version:

Sometimes it may be necessary to identify the SSH client that you are currently running and it’s corresponding version number, which can be identified as shown below. Please note that Linux comes with OpenSSH.

$ ssh -V
OpenSSH_5.8p1 Debian-1ubuntu3, OpenSSL 0.9.8o 01 Jun 2010

2. Login to remote host:

• The First time when you login to the remotehost from a localhost, it will display the host key not found message and you can give “yes” to continue. The host key of the remote host will be added under .ssh2/hostkeys directory of your home directory, as shown below.

$ ssh -l jsmith remotehost.example.com

Host key not found from database.
Key fingerprint:
xabie-dezbc-manud-bartd-satsy-limit-nexiu-jambl-title-jarde-tuxum
You can get a public key’s fingerprint by running
% ssh-keygen -F publickey.pub
on the keyfile.
Are you sure you want to continue connecting (yes/no)? yes
Host key saved to /home/jsmith/.ssh2/hostkeys/key_22_remotehost.example.com.pub
host key for remotehost.example.com, accepted by jsmith Mon May 26 2008 16:06:50 -0700
jsmith@remotehost.example.com password:
remotehost.example.com$

• The Second time when you login to the remote host from the localhost, it will prompt only for the password as the remote host key is already added to the known hosts list of the ssh client.

         $ ssh -l jsmith remotehost.example.com
         jsmith@remotehost.example.com password: 
         remotehost.example.com$

3. File transfer to/from remote host:

Another common use of ssh client is to copy files from/to remote host using scp.

• Copy file from the remotehost to the localhost:

 $ scp jsmith@remotehost.example.com:/home/jsmith/remotehostfile.txt remotehostfile.txt

• Copy file from the localhost to the remotehost:

 $ scp localhostfile.txt jsmith@remotehost.example.com:/home/jsmith/localhostfile.txt

Reference:

http://www.thegeekstuff.com/2008/05/5-basic-linux-ssh-client-commands/