SpamAssassin won’t do much if it hasn’t been trained. While it does come with a few plugins enabled for DKIM, SPF, RBL, and content checks, SpamAssassin is limited unless you train its Bayesian filter. The Bayesian filter will compare past content from known spam and ham emails to determine the likelihood of spam. Bayes' theorem, named after 18th-century British mathematician Thomas Bayes, is a mathematical formula for determining conditional probability.
Are you curious about SpamAssasin’s sa-update tool and what it does? As with many other programs geared towards servers, there are additional tools that are run inside of cron jobs and used by administrators. Knowing what these tools do and how they work can help you better understand your server and fix issues down the line. The sa-update tool is used to pull new configuration files and rules from channels. These new files are used by SpamAssassin to classify emails as spam in addition to the Naive Bayes filtering.
Keeping your MySQL server backup as current as possible is important. I’ve seen (and have done this myself) people backup using mysqldump once a day, week, or month without any backups in-between. There are a few problems with backing up your database this way. The first problem is that running mysqldump is very slow on large databases and could lockup your website for a significant portion of time. Secondly, you can lose all data that occurred since the previous backup.
Below is a glossary of terms often times used when discussing Virtual Private Servers, web hosting, and networking. Knowing what these following terms mean should help you navigate hosting provider websites and tutorials. Not all of the following terms are concrete in meaning and could be used to mean a slightly different concept. The glossary below is ordered alphabetically and tries to focus only on terms used when discussing virtual private servers.
Having a VPS provider that offers internal IP addresses and internal networking can greatly improve your app or website performance by removing the network latency between servers. In addition to improved performance, an internal IP address you can help improve your servers security by not publicly exposing services to the public. Keep in mind that some internal networks have other VPS clients on the same subnet. These clients can access your internal IP address.
There are times when you need to connect to your MySQL or MariaDB remotely but don’t want to enable remote connections on the server. The solution is to use SSH tunneling with OpenSSH. SSH tunneling works by forwarding requests from a client port to the SSH server. The SSH server will then forward the request to the destination which can be itself or any other host the SSH server can access.
SSH is the most valuable tool to manage your servers. As you already know, SSH allows you to remotely connect to your server and access a shell. With the power SSH possess, it’s important to protect SSH to ensure the only trusted people are able to connect. This post will go through the SSH configuration settings that need to be modified to help protect your server. Editing SSHD Configuration Files To prevent this tutorial from repeating itself too frequently, here is an overview of how to edit the /etc/ssh/sshd_config file.
Virtual Private Server providers that offer an API are a godsend. The need for an API really depends on how much control you need from your VPS provider outside of their website. As VPS providers start adding additional features, for instance configurable firewalls, API access then becomes more useful to help manage all of the additional services. There are many possible reasons why you would want API access to your VPS provider from simply expanding block storage on your server to creating new servers on the fly dynamically.
Below you will learn how to configure Nginx to stop logging sensitive information and help protect the privacy of your users along with protect authorization keys and query strings from being logged. Each section below outlines how to stop logging a specific page or piece of information. Multiple sections below can be combined to fully customize how you log visitors to your website. Basics to Nginx Log Options Before actually modifying any configuration files, here is an overview of the Nginx log options we will be using.
When managing any type of server, it’s generally wise to have a solution in place for when a server fails or when the server needs to be taken offline. When working on a high availability server setup, the question is how to quickly transfer activity from the failed or offline server to the backup server. One method is to use IP failover, which is the focus of this post. In short, IP failover is the method of moving the IP address of the failed server to the backup server, allowing requests to be handled by the backup server until the main server is once again functional.