2018-07-10 (last updated at January 10th, 2019) Michael BoelenSSH 6 comments

OpenSSH security and hardening

SSH or Secure Shell is the popular protocol for doing system administration on Linux systems. It runs on most systems, often with its default configuration. As this service opens up a potential gateway into the system, it is one of the steps to hardening a Linux system. This article covers the SSH security tips to secure the OpenSSH service and increase the defenses of the system. OpenSSH security OpenSSH is under development by the security fanatics from the OpenBSD project. Every new […]

2016-07-12 (last updated at September 2nd, 2018) Michael BoelenSSH 12 comments

Using Ed25519 for OpenSSH keys (instead of DSA/RSA/ECDSA)

Introduction into Ed25519 OpenSSH 6.5 added support for Ed25519 as a public key type. It is using an elliptic curve signature scheme, which offers better security than ECDSA and DSA. At the same time, it also has good performance. This type of keys may be used for user and host keys. With this in mind, it is great to be used together with OpenSSH. In this article, we have a look at this new key type. DSA or RSA Many […]

2015-03-16 (last updated at December 18th, 2015) Michael BoelenSSH, System Administration One comment

Using SSH keys instead of passwords

Using SSH keys instead of passwords Linux systems are usually managed remotely with SSH (secure shell). Still many administrators are using passwords, instead of keys. Keys not only boost security, it also makes managing systems much easier. Instead of entering your password for each server, you only have to do it once per session. When managing several systems per day, you will be wondering why you ever used password based authentication before. Creating the key Depending on your desktop platform, […]