OpenBSD related tutorial/FAQ

How to install and configure OpenVPN client on OpenBSD

June 21, 2018June 21, 2018in Cryptography, Networking, OpenBSD, OpenVPN last updated June 21, 2018

I have a file named openvpn.client.ovpn. How do I use this file to connect my OpenBSD based desktop to remote OpenVPN server and setup secure VPN? How do I configure OpenVPN client on OpenBSD Unix system?

How to patch Meltdown vulnerability on OpenBSD Unix

March 4, 2018April 20, 2018in OpenBSD, Security, UNIX last updated April 20, 2018

I read that OpenBSD is the first BSD family of the operating system to release updates for its stable releases to mitigate the Meltdown vulnerability. How do I patch Meltdown on OpenBSD Unix operating system?

How to exclude file when using scp command recursively

December 28, 2017December 29, 2017in FreeBSD, Linux, OpenBSD, UNIX last updated December 29, 2017

I need to copy all the *.c files from local laptop named hostA to hostB including all directories. I am using the following scp command but do not know how to exclude specific files (such as *.out):
$ scp -r ~/projects/ user@hostB:/home/delta/projects/
How do I tell scp command to exclude particular file or directory at the Linux/Unix command line?
Continue reading

How to use/run bash aliases over ssh based session

December 26, 2017December 26, 2017in BASH Shell, Linux, OpenBSD, Troubleshooting, UNIX last updated December 26, 2017

I have set up a bash alias named file_repl. It works entirely when I log in using ssh command. However, my bash aliases are not running over ssh, for example:
$ ssh vivek@server1.cyberciti.biz file_repl bash: file_repl: command not found
How do I run bash shell aliases when I use ssh command?

How to install keychain manager for ssh-agent on CentOS 6/7

December 4, 2017February 2, 2018in CentOS, Linux, OpenBSD, Package Management, RedHat and Friends last updated February 2, 2018

OpenSSH offers RSA and DSA authentication to remote systems without supplying a password. keychain is a special bash script designed to make key-based authentication incredibly convenient and flexible. It offers various security benefits over passphrase-free keys. How do I install keychain on a CentOS Linux 6.x or 7.x?

How to find disk I/O latency with ioping monitoring tool on Linux

September 21, 2017in FreeBSD, Linux, Mac OS X, OpenBSD, UNIX last updated September 21, 2017

How do I monitor disk I/O latency in real time on Linux, FreeBSD, OpenBSD, and MacOS operating system?

How To Set Up PF Firewall on FreeBSD to Protect a Web Server

August 29, 2017January 14, 2018in FreeBSD, OpenBSD, PF Firewall, Security last updated January 14, 2018

I am a new FreeBSD server user and moved from netfilter on Linux. How do I setup a firewall with PF on FreeBSD server to protect a web server with single public IP address and interface?

nixCraft