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OpenSSH

How to Setup Reverse SSH Tunnel on Linux

Reverse SSH is a technique that can be used to access systems (that are behind a firewall) from the outside world. As you already know SSH is a network protocol that supports cryptographic communication between network nodes. Using this protocol, you can do a secure remote login, secure copy from/to a remote machine etc. You'll [...]

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Question: When I perform rsync, it asks for my password on the remote server before starting the transfer. I would like to avoid this, and perform rsync without password. Can you explain with an example on how to setup rsync over ssh without password on Linux? Answer: The following steps explains how to setup rsync [...]

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OpenSSH options are controlled through the /etc/ssh/sshd_config file. This article explains the 7 default options in sshd_config file that you should change. In sshd_config, the lines that start with # are comments. For those options that uses the default values, the sshd_config file contains a commented line with the option and its default value. This [...]

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Question: When I'm trying to ssh to a remote server, after I enter the username, it takes a lot of time before it displays the password prompt. Basically, my SSH ( openSSH ) is slow during authentication process. How do I solve this problem? Answer: If your ssh login from localhost to remotehost is slow, [...]

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How To Fix Offending key in ~/.ssh/known_hosts file

As we discussed earlier in our basic ssh client commands article, when you do ssh to a machine for the 1st time (or whenever there is a key change in the remote machine), you will be prompted to say 'yes' for authenticity of host. This feature is controlled using StrictHostKeyChecking ssh parameter. By default StrictHostKeyChecking [...]

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When you have the password-less login enabled, you may be either using SSH to execute command in the batch mode on a remote machine or using SCP to copy files from/to the remote machine. If there are some issues with the password less login, your batch program may end up in a loop or timeout. [...]

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You can login to a remote Linux server without entering password in 3 simple steps using ssky-keygen and ssh-copy-id as explained in this article. ssh-keygen creates the public and private keys. ssh-copy-id copies the local-host's public key to the remote-host's authorized_keys file. ssh-copy-id also assigns proper permission to the remote-host's home, ~/.ssh, and ~/.ssh/authorized_keys. This [...]

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In our previous articles, we discussed how to setup ssh key based authentication to perform ssh and scp without password under the following three scenarios: OpenSSH to OpenSSH OpenSSH to SSH2 SSH2 to SSH2 In this article, I'll explain how to perform ssh and scp from SSH2 (local-host) to OpenSSH (remote-host) with no password. In [...]

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