One of the most popular command-line utilities is the find command, mainly because of its simplicity and versatility. It’s the default option to search for files across multiple UNIX based systems with a wide range of parameters and variables to narrow down our searches. It helps look for files matching a specific name, date, size, or even owner to provide a frame to append other commands to the list of files found. The basic structure of the find command is as follows.
Knowing your server’s IP address(s) can be useful information to have for various reasons. After all, other than your domain, the server’s IP is the main address used to reach the server. Knowing a server’s IPs may be necessary when making changes to: DNS, networking, and security. A server may have a single IP, or multiple IPs, but sometimes, you may need a quick method to double-check since it’s easy to forget.
Just as regular visitors reach our server every day, so do others with more nefarious intentions. It is simply not reasonable to run an online service without some layer of protection. To protect against some of these attacks, Ubuntu ships with ufw (Uncomplicated Firewall). This is a tool designed to make Ubuntu firewall management as easy and user-friendly as possible. Specifically, ufw provides a cleaner interface for the core firewall tools netfilter and iptables, which, while robust, can be challenging to master.
Remote Desktop Protocol (RDP) is the easiest and most common method for managing a Windows server. Included in all versions of Windows server and has a built-in client on all Windows desktops. There are also free applications available for Macintosh and Linux based desktops. Unfortunately, because it is so widely used, RDP is also the target of a large number of brute force attacks on the server. Malicious users will use compromised computers to attempt to connect to your server using RDP. Even if the attack is unsuccessful in guessing your administrator password, just the flood of attempted connections can cause instability and other performance issues on your server. Fortunately, there are some approaches you can use to minimize your exposure to these types of attacks.
The hosts file is a local plain text file that maps servers or hostnames to IP addresses. This file has been in use since the time of ARPANET. It was the original method to resolve hostnames to a specific IP address. The hosts file is usually the first process in the domain name resolution procedure. Here is an example of a hosts file entry.
In some ways, firewalld on systemd systems is easier to manage and configure than iptables. There are, for the most part, no long series of chains, jumps, accepts and denies that you need to memorize to get firewalld up and running in a basic configuration. The rules are simple and straightforward, but there is no reason you cannot still have all the power that iptables afforded.
A DNS Zone is part of a group of components that make up DNS. These objects are managed by an administrator or organization in a granular manner. DNS zones can contain varied information about a domain and subdomains. Multiple zones can also exist on the same server. DNS information is stored within a text file called a DNS zone file.
DNS stands for Domain Name System (DNS) services. When we access a website, we are using this service to locate the server where the domain’s website is located. When browsing the web, we usually type in a domain name like www.google.com into our browser. This is better than trying to remember an IP address linked to a Google server.
The purpose of DNS is typically used to resolve a domain name to an IP address. This act is known as a forward resolution and is performed every time you visit a site on the internet. Reverse DNS (or rDNS), as its name implies, is a method of resolving an IP address back to a domain name.
nmcli stands for Network Management Command-Line Interface, and is a tool for managing the NetworkManager application and reporting on the status of the network. It can be utilized as a substitution for nm-applet or other similar graphical clients. nmcli is used to display, create, delete, edit, activate, deactivate network connections, and control and display network device status.
Typical uses include:
Scripts: Utilize NetworkManager via nmcli rather than managing network connections manually. nmcli supports a terse output format that is healthier fitted to the script process. Note that NetworkManager can even execute scripts, referred to as “dispatcher scripts,” responding to network events.
Servers, headless machines, and terminals: nmcli tool can be used to control NetworkManager without a graphical user interface, including creating, deleting, editing, starting and stopping network connections as well as viewing network status.