Simple Linux UFW Example
Allow a connection from a particular remote IP address to any IP address on the local machine on a specific port (TCP & UDP). Verify with:
Linux
Ubuntu 22.04 LTS Network Bonding – Active/Standby
Setting up network bonding between two 10Gbit NICs within a physical machine; this assumes Active-Standby bonding so a link down event on one NIC will cause the other to become Active, no LACP or switch side configuration is required in this case. The documentation assumes you are running under root, stick sudo in front of … Read more
Create a Linux User Account (Ubuntu)
Creating a user account with a home directory and setting the default shell as BASH, can be done as follows, add “sudo” to the front as required. If you need your account to have sudo rights, you can specify the “sudo” group upon creation, as follows:
“Password Less” Sudo
A quick example on Ubuntu Linux 22.04 LTS. I had the need for a particular user to have “passwordless” sudo ability. Its not best practice to do this, however if you are restricting the command or commands that a user can run with “passwordless sudo”, you are balancing functionality and security as well as you … Read more
SNMPWalk 101
SNMP (Simple Network Management Protocol) is a protocol that can be used for monitoring and managing network connected devices. Personally I use it primarily for monitoring, it is a useful way to interrogate network connected devices for information about their status. For example querying to identify if a power supply has failed on a switch, … Read more
NagiosXI – REST API to Manipulate Objects
NagiosXI has a REST API that can be used to add, edit and remove objects from the configuration. Full details of the configuration and use of this can be found on your installation at: http://nagiosserver.domain.com/nagiosxi/help/?xiwindow=api.php (or you can find it through the Advanced Configuration menu). Each user has an APIKey which can also be found via … Read more
Quick Guide – SSH Public Key Authentication (Ubuntu Linux)
A quick guide to setting up SSH Public Key Authentication. SSH Public Key Authentication means you can authenticate to a remove server via SSH without needing to enter your username and password. Instead you create a public-private key pair, then place the public key on the target server. Then when you SSH to the server … Read more
Linux Screen Basics
The “Screen” command is a very useful utility that allows you to create a session (or sessions) which you can run programs in, but in such a way that you can detach from the session (screen) if you needed to logoff your terminal or reboot your client machine, but without loosing what you were doing … Read more
Quick Guide – NFS Server Install on Ubuntu Linux
You can deploy an NFS server onto an Ubuntu Linux server to allow you to provide NFS exports to other machines on your network. The documentation below provides a very quick guide on how to do this. It assumes you have a Ubuntu Linux 22.04 LTS machine with some storage attached that you want to … Read more
Installing a Specific Ruby Version
We needed to install Ruby 2.7 instead of what normally comes with Ubuntu 20.04 LTS, if we installed a later than 2.7 Ruby version, the particular application (i.e. Staytus in this case) would barf. The nice people at BrightBox have created some packaged installs of Ruby at various versions.https://www.brightbox.com/docs/ruby/ubuntu/#adding-the-repositoryhttps://launchpad.net/~brightbox/+archive/ruby-ng (Latest version supported 20.04) We first … Read more