Time to time you may find the need to encrypt a file before sending it to someone or store it where other people may have access to it. OpenSSL is a great tool for this and it is installed on most Linux/Unix and OS X (also, I believe there is an install for OpenSSL for Windows too). Here’s the command to encrypt a file, $ openssl enc -aes-256-cbc -a -salt -in mytestfile.

“This was a triumph.” If you find your SSH connections dropping or locking up after not being used for some time you may want to try to edit your ssh_config (/etc/ssh/ssh_config) file and uncomment/add in the line ServerAliveInterval 30. The number is in seconds. What this will do is send a small ‘keep-alive’ packet to the server to ensure you don’t get dropped. Why is this happening? It could be settings on the server that drop users after set time of inactive use or due to a firewall/switch rule that drop inactive connections to improve the performance of the network.

SSH is one of my favorite tools on a Linux/Unix system. There is so much you can do from copying files, to tunneling data security. SSH is a great way to get access to your system at home, but also access to your network. Lets go over some things about SSH tunneling and why it’s good to use! Basic Idea: The idea of tunneling is to give you a secure way to pass data from one point to another.

Ok, lets start with something easy! :) What are SSH keys: SSH keys are a way to allow someone access to a user on another system without the need for a password. This is done with 2 key files one that is public and the other private. This is called “Public-key cryptography”. The public key will be sent to the server that you want to connect to and the private will stay on your local (or client) system.