TechRecipes

By default, most SSH servers are configured to forcibly disconnect inactive or idle clients, or actually those with no network activity. This is not good for some people especially if one is setting up a (reverse) tunnel to the server where the tunnel should remain established whenever they need it.
There are 2 methods to overcome [...]

SSH in most system by default allow login using password. While this is the common setting, there are time that the users need to be enforced to used stronger means of authentication, such as passphrase protected public key. The option to allow password login is  PasswordAuthentication in the /etc/sshd_config configuration file. If it is not [...]

SSH in most system by default allow login using public key. While this is convenient, it is a security risk when unauthorized person manage to get the private key, especially when the key is not protected by any passphrase. The option to allow public key authentication is PubkeyAuthentication in the /etc/sshd_config configuration file. If it [...]

SSH SOCKS proxy is one of the way to have a secure tunnel for web browsing. It’s comes handy when we need to do secure browsing in a public network such as in a public WiFi environment, as the traffic between our host and the proxy is encrypted .
For this to work, we need to [...]

SSH by default allow everyone in the local system with a login shell to login remotely through SSH. This includes the root user. The option to whether allow root login or not is PermitRootLogin in the /etc/sshd_config configuration file. If it is not set, SSH daemon will allow root login.
For security reason it’s good to [...]

SSH by default runs on one port only, which by default is 22.There are times however that we might want to run SSH in more than just one port.
Which port SSH daemon is run is set by the Port option in the /etc/sshd_config configuration file. If it is not set, SSH daemon will run on [...]

SSH by default runs on port 22.There are times however that it need to be run on other ports, say when the firewall only allow certain ports but not port 22, or just to prevent from SSH bruteforce from bots that automatically attack port 22.
Which port SSH daemon is run is set by the Port [...]

The first step is to (optionally) generate RSA key for use with SSH. Dont enter any passphrase for this to work.

shakir@herugrim ~ $ ssh-keygen -t rsa -C shakir@192.168.1.10
Generating public/private rsa key pair.
Enter file in which to save the key (/home/shakir/.ssh/id_rsa): /home/shakir/.ssh/id_rsa.192.168.1.10
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/shakir/.ssh/id_rsa.192.168.1.10.
Your [...]

From it’s man page, rsync is a program that behaves in much the same way that rcp does, but has many more options and uses  the  rsync  remote-update  protocol  to greatly  speed  up file  transfers  when the destination file is being updated.
The rsync remote-update protocol allows rsync to transfer just the differences between two sets [...]

When trying to SSH to another machine and getting the following message;

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!

the error is probably caused by the SSH key on the other machine to have changed as compared to the one stored in ~/.ssh/known_hosts
To fix this problem is [...]