By default Apache will serve web content out over the wire in the clear via HTTP which is insecure. We can increase the security between clients and the web server by using HTTPS. This will encrypt the data transferred between the two and is done by configuring TLS.
Here we will add HTTPS support for our test domain www.example.com, which we previously configured in our virtual host configuration guide.
Read more »
In Apache (httpd) virtual hosts are used to host web content for multiple domains off of the same server depending on the IP address or domain name that is being used. Depending on the request received different virtual host configuration can apply, resulting in different settings and web content being served from a single web server. For example a web server with one IP address can host multiple domain names such as example.com and example.org and many more.
Here we are going to cover how to configure virtual hosts for Apache 2.4 so that we can have multiple domains serving different websites based on what is requested.
Studying for your RHCE certification? Checkout our RHCE video course over at Udemy which is 20% off when you use the code ROOTUSER.
DNS resolution is an important service, without it functioning properly domain names will not be correctly resolved to IP addresses preventing other network services from working correctly. Therefore it is equally important to know how to troubleshoot DNS issues on a Linux client and fix any problems to reduce disruption.
There are multiple potential points of failure during the DNS lookup process such as at the system performing the lookup, at the DNS cache, or on an external DNS server. Here we will cover how to check these and perform various tests to identify where exactly the problem lies.
DNS resolution is used to lookup a domain name and resolve it to an IP address. Instead of having various systems in our network querying directly out to the Internet, we can configure a DNS caching server within our network and have other systems point to this for DNS resolution which will improve efficiency. The more systems sending queries through the caching server, the larger the cache will grow, further improving the hit rate.
The local cache of DNS records is stored closer to the systems initiating the requests, resulting in faster resolution time. These records will be cached until their TTL expires, or the cache is flushed. If any other system performs a DNS lookup for a query that resides in the cache it can be returned much faster as the caching server will not have to forward the query to some other DNS server out on the Internet.
There are many packages capable of acting as a DNS cache such as Bind, Dnsmasq and Unbound. In our example we will be working with Unbound.
It is critical to regularly take a backup of important data that is stored within a database so that the data can be restored in the event of any problem. Examples of such problems include database server failure, data tampering, corruption and any other number of file system specific problems that are looking to do your database harm.
Here we will cover how to backup and restore an SQL database from MariaDB/MySQL. Read more »
SSH keys can be used to increase the level of security for a user remotely authenticating to a Linux server through SSH. SSH keys are typically preferable in terms of security when compared to passwords as they are far less vulnerable to brute force attack, there is simply a lot more entropy in a key than password.
Here we are going to cover how to configure and use key-based authentication for SSH in Linux. Read more »
MariaDB is a drop in replacement for MySQL and is an open source fork of MySQL created by the original MySQL developers. As of Red Hat Enterprise Linux (RHEL7) and CentOS 7 MariaDB is now the default SQL database, rather than MySQL which was the default in previous releases of the operating system.
Here we’re going to cover how to install and configure MariaDB.
In many Linux based operating systems such as Debian 8, Red Hat Enterprise Linux (RHEL) and CentOS 7 systemd is now the default init system and is used for service management.
Here we will cover service management with the systemctl command, which is used to control the state of the systemd system and service manager.