In several of our tutorials, we have referred to the IP address of a server. However, for many, the concept is not entirely clear. Today, I will show how to set a Static IP address using CentOS7.
IP means “Internet Protocol“. An IP address is a number (or set of numbers) that logically and hierarchically identifies a network interface (communication/connection element) of a device (computer, tablet, laptop, smartphone) that uses the IP protocol. Every web page you visit, any computer you work from or even mobile phones and tablets, has one of these addresses when you access the internet.
According to the form and scope of IP addresses, they can be classified into Public and private; static and dynamic; Type A, B or C. Despite all of them, I will focus on dynamic and static IP.
Dynamic IP Address and Static IP Address
In short, a dynamic IP address is one that is obtained via a DHCP server. Among its main advantages are:
- Reduces the amount of assigned IP inactive.
- It provides more security because your IP can change constantly.
- IP addresses are assigned by a server.
Otherwise, static IP addresses are assigned manually by a user and will not change until the user assigns another. Nonetheless, a router can also assign this type of address through the device’s MAC address. Its main advantage is that it is easier to deploy network services. However, it is a slightly less secure method as the IP address will never change.
How to do it in CentOS 7
First, you must know what address and what the network interface is called. To do this, open a terminal and run as root user:
:~# yum install net-tools
Then, verify the name of the network interface:
:~# ip addr show
In this case, the interface name is enp0s3. In this section, you can also see the IP address of the computer.
Now you need to edit the interface configuration file.
:~# nano /etc/sysconfig/network-scripts/ifcfg-enp0s3
This is the contents of the file in my case.
TYPE=Ethernet PROXY_METHOD=none BROWSER_ONLY=no BOOTPROTO=dhcp DEFROUTE=yes IPV4_FAILURE_FATAL=no IPV6INIT=yes IPV6_AUTOCONF=yes IPV6_DEFROUTE=yes IPV6_FAILURE_FATAL=no IPV6_ADDR_GEN_MODE=stable-privacy NAME=enp0s3 UUID=195e564e-ecc4-477f-89ae-7158db8562fe DEVICE=enp0s3 ONBOOT=yes ZONE=public
Of all this, you only have to modify BOOTPROTO to static and add the following:
IPADDR=YOUR_IP PREFIX=24 GATEWAY=YOUR_GATEWAY DNS1=DNS_IP DNS2=DNS_IP
These are the parameters that you must place in your case that require. For example, the IP can be the one you want, and the gateway depends on your network. DNS values are optional.
Finally, restart the network service.
:~# systemctl restart network
Then, verify the IP address.
:~# ip addr show
And that’s it.
As you could see, it’s easy to make the change to the static IP address in CentOS 7. Remember that the configuration parameters are changeable and you must have them for your connection to be correct.
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