Hello Dev, are you looking to host your own DNS server? Perhaps you want to have more control over your website’s domain name system, or maybe you want to learn about networking and server management. Whatever your reason, this guide will walk you through the steps of setting up your own DNS server. Let’s get started!
What is a DNS Server?
A DNS (domain name system) server is a computer server that translates domain names (such as example.com) into IP addresses (such as 192.168.1.1). This allows computers and devices to communicate with each other over the internet using human-friendly domain names instead of numerical IP addresses. When you type a domain name into your web browser, your computer sends a request to a DNS server to resolve the domain name into an IP address.
There are two types of DNS servers: authoritative and recursive. Authoritative DNS servers store the official DNS records for a specific domain name, while recursive DNS servers provide DNS resolution services to clients by querying authoritative DNS servers on their behalf. In this guide, we will be setting up an authoritative DNS server for your domain name.
Choosing a DNS Server Software
There are several DNS server software options to choose from, including BIND, PowerDNS, and NSD. In this guide, we will be using BIND (Berkeley Internet Name Domain), which is one of the most widely used DNS server software packages in the world. BIND is open-source and free to use, and it runs on most operating systems, including Linux, Windows, and macOS.
Installing BIND
Before we can start configuring our DNS server, we need to install BIND on our server. The installation process will vary depending on your operating system, but the following commands should work for most Linux distributions:
Operating System |
Command |
|---|---|
Ubuntu/Debian |
sudo apt-get install bind9 |
CentOS/Fedora |
sudo yum install bind |
Arch Linux |
sudo pacman -S bind |
Once BIND is installed, we can start configuring our DNS server.
Configuring BIND
Creating a Configuration File
The first step in configuring BIND is to create a configuration file. This file will specify the basic settings for our DNS server, such as the domain name we want to serve and the IP address of our server. By convention, BIND configuration files are named named.conf, so we will create a file with that name:
$ sudo nano /etc/named.confIn the configuration file, we will define our domain name and set up a few basic options. Here is an example configuration:
options {directory "/var/cache/bind";recursion no;};zone "example.com" {type master;file "/etc/bind/db.example.com";};The options section specifies the location of the BIND cache directory and disables recursion, which prevents our DNS server from acting as a recursive resolver for other clients. The zone section specifies the domain name we want to serve and the type of DNS server (in this case, a master server).
Creating a Zone File
Now that we have defined our domain name in the configuration file, we need to create a zone file that specifies the DNS records for our domain. The zone file will contain resource records (RRs) that map domain names to IP addresses, among other things.
The zone file for our example.com domain will be named db.example.com and will be located in the /etc/bind/ directory. Here is an example zone file:
$ORIGIN example.com.$TTL 86400@INSOAns1.example.com. hostmaster.example.com. (2019010101 ; serial number28800; refresh7200; retry604800; expire86400; minimum TTL)INNSns1.example.com.INNSns2.example.com.ns1INA192.168.1.1ns2INA192.168.1.2wwwINA192.168.1.3The first line ($ORIGIN example.com.) sets the origin of the zone file to our domain name. The $TTL line sets the default time-to-live (TTL) value for our DNS records (in this case, 86400 seconds, or one day).
The next line specifies the start of authority (SOA) record for our domain, which contains information about the domain’s primary nameserver and the contact information for the administrator.
The two NS records specify the nameservers for our domain, which in this case are ns1.example.com and ns2.example.com.
The next two lines specify the IP addresses for our nameservers.
Finally, the last line specifies the IP address for the www subdomain. You can add additional resource records for other subdomains as needed.
Testing Your DNS Server
Now that we have configured our DNS server, it’s time to test it. First, we need to start the BIND service:
$ sudo systemctl start namedNext, we need to make sure that our DNS server is listening on the correct IP address and port (53). We can use the netstat command to check:
$ netstat -lnp | grep namedtcp00 127.0.0.1:530.0.0.0:*LISTEN1234/namedtcp600 ::1:53:::*LISTEN1234/namedudp00 127.0.0.1:530.0.0.0:*1234/namedudp600 ::1:53:::*1234/namedIn this example, we can see that named is listening on the loopback address (127.0.0.1) on port 53. We want our DNS server to be accessible from other computers on the network, so we need to change this setting in our configuration file.
To edit the configuration file again, type:
$ sudo nano /etc/named.confThen add the following line to the options section:
listen-on port 53 { any; };This will allow BIND to listen on any IP address for incoming DNS requests.
Save and exit the file, then restart the BIND service:
$ sudo systemctl restart namedNow that our DNS server is up and running, we can test it by querying it for the IP address of our www subdomain:
$ nslookup www.example.comIf everything is working correctly, you should see the IP address that you specified in your zone file:
Server:127.0.0.1Address:127.0.0.1#53Name:www.example.comAddress:192.168.1.3Conclusion
Congratulations, Dev! You have successfully set up your own DNS server using BIND. By hosting your own DNS server, you have more control over your domain name system and can improve the performance and reliability of your website. If you have any questions or run into any issues, please refer to the FAQs below or consult the official BIND documentation.
FAQs
What is a DNS record?
A DNS record is a piece of information in a DNS database that maps a domain name to an IP address, or to other DNS records. DNS records are used to resolve domain names to IP addresses so that computers can communicate with each other over the internet.
What is a TTL value?
A TTL (time-to-live) value is a setting in a DNS record that specifies how long the record should be cached by other DNS servers. When a DNS resolver queries a DNS server for a record, the server includes the TTL value in the response. The resolver then caches the record for the duration of the TTL value, after which it must query the server again to get the updated record.
What is recursion?
Recursion is a process by which a DNS server queries other DNS servers on behalf of a client to resolve a domain name to an IP address. If recursion is enabled on a DNS server, it will act as a recursive resolver, querying other DNS servers as needed to resolve domain names. If recursion is disabled, the server will only serve authoritative DNS records for its configured domains.
What is an authoritative DNS server?
An authoritative DNS server is a DNS server that has the official DNS records for a specific domain name. When a client needs to look up a domain name, it sends a request to an authoritative DNS server for that domain. The authoritative server responds with the requested resource record or an error message if the domain name is not found.
What is a master DNS server?
A master DNS server is a type of authoritative DNS server that stores the primary zone file for a domain. The master server is responsible for making changes to the zone file and propagating those changes to any secondary (slave) DNS servers that are configured for the domain.
What is a slave DNS server?
A slave DNS server is a type of authoritative DNS server that copies the zone file from a master DNS server and uses it to serve DNS requests for the domain. The slave server periodically checks for updates to the zone file from the master server and updates its own copy as necessary.