How to set up two-factor authentication for SSH login on Linux

With many high-profile password leaks nowadays, there is a lot of buzz in the industry on “multi-factor” authentication. In a multi-factor authentication system, users are required to go through two distinct authentication procedures: providing something they know (e.g., username/password), and leveraging something they have “physical” access to (e.g., one-time passcode generated by their mobile phone). […]
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How to remote control Raspberry Pi

Once you have a fully working Raspberry Pi system, it may not be convenient for you to continue to access Raspberry Pi directly via a keyboard and HDMI/TV cable connector dedicated to Raspberry Pi. Instead, you will want to remote control “headless” Raspberry Pi from another computer. In this tutorial, I will show you how […]
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How to access ssh terminal in web browser on Linux

Running “everything” in a web browser used to be a bold statement. However, due to the powerful HTML5/JavaScript stack, a web browser increasingly becomes a dominant application delivery platform. Even the Linux kernel sandboxed in a web browser no longer sounds so crazy these days. In this tutorial, I describe how to access an SSH […]
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How to synchronize files between two servers

Suppose you have a collection of files which are replicated on two different servers. The two replicas are then modified independently, and you want whatever changes made in one replica to be propagated to the other, so that both replicas remain in sync. There are several file mirroring tools on Linux, such as rsync or […]
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How to create a secure incremental offsite backup in Linux with Duplicity

If you maintain mission-critical data on your server, you probably want to back them up on a remote site for disaster recovery. For any type of offsite backup, you need to consider encryption in order to avoid any unauthorized access to the backup. In addition, it is important to use incremental backup, as opposed to […]
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How to speed up X11 forwarding in SSH

When you are running X applications over SSH, the encryption/decryption overhead of the SSH protocol may slow down the rendering of remotely running X applications. Furthermore, if an SSH session is established over a wide area network, X11 forwarding over SSH may become even slower due to network latency and throughput limitation. In this tutorial, […]
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How to set up VNC over ssh

By nature, VNC is not a secure protocol. A well-known security risk of VNC is that you connect to a VNC server via an unencrypted channel across the network. Thus anyone can snoop on an established VNC session. To protect against VNC sniffing, you should try additional out-of-band encryption mechanism, underneath or on top of […]
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