SSH key generation

We will be ended up by re entering the password when ever we connect to a remote machine using ssh.

Here is the way to avoid re entering the password each and every time by generating a key pair Id and moving to remote machine only once.

ssh-keygen -t dsa

Generating public/private dsa key pair.

Enter file in which to save the key (/home/localuser/.ssh/id_dsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/localuser/.ssh/id_dsa.
Your public key has been saved in /home/localuser/.ssh/id_dsa.pub.
The key fingerprint is:
93:58:20:56:72:d7:bd:14:86:9f:42:aa:82:3d:f8:e5 localuser@mybox.home.com

scp ~/.ssh/id_dsa.pub username@remotemachine:.ssh/authorized_keys


login to remote machine

chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys

Facing problem with X11

I've faced some problem with X11 forwarding. Then I analsyed the X process using ps -ef | grep X

I found the X process initialized has the argument--nolistentcp. Actually this prevents the tcp connection for X11. So make sure this is disabled in gdm.conf.

I came to know there is a entry in /etc/X11/gdm/gdm.conf which prevents the TCP connection.

after altering the "DisallowTCP"=false.

and restart the X windows.

To restart X windows CRTL + ALT + backspace or restart the system.

Basic X11 Forwarding Over SSH

X11Forwarding needs to be enabled on the sshd server. Do this by making the following edit:
File: /etc/ssh/sshd_config

After you make these changes, you will need to restart sshd so the changes will be accepted:
/etc/init.d/sshd restart

Don't forget to log out and log in to the server for this change to take effect.

Note: one reason for receiving the error messages

xterm Xt error: Can't open display: your_client_name:0.0

may be that X11Forwarding is not enabled on the server.
[edit] Running single apps

$ ssh -X < remote_server >

Powerfully using SSH

This is the article which gives good ideas to use SSH powerfully

http://polishlinux.org/apps/ssh-tricks/#