Nowadays, it's not uncommon for a computer to have multiple network interfaces. For example, if you're using a laptop (other than an Ultrabook), it's likely that you have a wired, as well as a wireless, network interface. Each network interface will have its own IP address and they operate independently of each other. In fact, you can even route traffic between multiple interfaces, though this is typically disabled by default in most Linux distributions. Just like each interface has its own IP address, each will also be identified by the system by its own device name. Before we discuss this further, go ahead and take a look at the device names on your system. Open up a terminal and type the following command:

ip addr show

Your output will look like this:

The output of the ip command, showing network interfaces and address assignments

In this example, we see three network interfaces listed. The first, lo, is the local loopback adapter. The second listing...

On a network, it's much more convenient to look up other resources by name, rather than remembering the IP address of every resource we connect to. By default, looking up hosts by name may not function without a little configuration. For example, you can try the ping command against the name of one of your Linux machines, and you may or may not get a response. This is because a DNS entry for the resource you're connecting to might not exist. If it doesn't, you'll see an error similar to the following:

ping: unknown host potato

However, if you ping the device by its IP, it would more than likely respond:

64 bytes from 10.10.96.10: icmp_seq=2 ttl=64 time=0.356 ms

The reason for this is in order for a network host to be able to contact another, it needs to know its IP address. If you type in a name instead of an IP...

For quite some time, net-tools has been the suite of tools used to manage network connections on Linux systems. The net-tools suite includes commands such as ifconfig, route, netstat, and others (which we'll discuss shortly). The problem with net-tools is that it hasn't been updated by its developers in well over a decade, making many distributions opt to abandon it in favor of the iproute2 suite, which offers the same functionality (but with different commands to achieve the same goals). Even though net-tools are being deprecated, quite a few distributions still include it. For example, Debian includes both iproute2 and net-tools, so you can use commands from either suite. In CentOS, iproute2 is present though net-tools is not installed by default. If you would like to utilize the older net-tools, you can install it in CentOS with the following command:

# yum install net-tools

So, why would you want to install net-tools if it&apos...

In most cases, after you install your desired distribution of Linux, it receives an IP address via DHCP and away it goes. Whether you're using a graphical desktop environment or a shell environment with no GUI, the magic mostly happens in the background. While there are GUI tools to manage your network connections, anything you can do via a graphical tool, you can do via the shell. In the case of servers, there may not be a graphical environment at all, so learning how to manage your network connection via the shell is very important. In this section, we'll discuss the method for manually configuring an interface in Debian, and then discuss how to do the same thing with CentOS.

In the previous section, two methods were discussed for finding your current IP address. Depending on whether your distribution ships net-tools or iproute2, you can use one method or the other (or both). Of course, that's the first step. Do you have a connection...