In this tutorial we want to install DNS on Windows Server, but before that, we ask What is DNS and Why do we use it?
What is DNS and Why do we use it?
The DNS system is a process for addressing a domain name to an IP address. Since it is difficult to remember the IP, we can use this process to consider a name for each address, and when we type the domain name, the IP address will call automatically.
Domain name servers or DNS contain a database that stores all public domains and their corresponding IP addresses. DNS translates domain names to IP addresses. For example, whenever you type google.com on your browser, your request first goes to the DNS servers and by the DNS servers, that name translate into an IP address and through it, it connects to the website server and in Finally, you can see the website in your browser.
Sometimes, when you send a request to the DNS, it may not be able to find the IP address of the desired website, in this case, the first level DNS sends a request to the root level and asks for the IP address, and if from that level No results receive too, the request will send for the top-level domain (TLD).
Usually, the first level of request will be sent to Internet Service Providers (ISP).
Why do we use it?
We use this process for all devices connected to the Internet and it is particularly important to work with the Internet. Usually, you don’t need to worry about this or do anything special, because the ISP automatically translates DNS server address by the ISP for you.
In this tutorial we want to try Firewall in CentOS but before that we ask: What is a firewall? Firewalls are the first line of defense in network security. They are a network security device that can be hardware or software and control incoming and outgoing traffic.
Firewall is a part of network security that controls and filters traffic. The firewall place between the Internet and the end user and filters the Internet based on the rules previously defined for it and whether it allows access or not.
In Linux, Netfilter use to allow access or deny access to network traffic. Filtering packages and their management is particularly useful and important for management in an organization.
If a package enters the server, we need Netfilter to check it so that we can check it according to the rules and allow access or not.
A firewall is a set of rules, and when a packet tries to pass through it, its contents are checked according to the rules of the firewall. A firewall is a tool for managing firewall rules on any Linux machine and it can also be described as a device that examines network traffic (outgoing/incoming connections) and makes traffic decisions.
Now we try to install it in CentOS:
In during this tutorial, we try to Start, Stop, Enable or Disable
First, we check status by command systemctl
If it was inactive in setting let to start it, after starting it, we can check again status.
there are four options to check firewalld that we can use:
[start/stop/disable/enable]
this command is for checking status:
$systemctl status firewalld.service
firewalldis a dynamic firewall that provides support at the trust level of connections or network interfaces and supports IPv4, IPv6 protocols.
