How To Configure Basic DNS in Linux Operating Systems?
In today’s article, we will learn how to do Basic DNS Configuration (dnsmasq
) in Linux Operating Systems. For us, “dnsmasq
“, which we will use for name resolution in small-scale network structures, will analyze the records we enter in our server’s “/ etc / hosts
” file without requiring a very large configuration. will provide the possibility.
Now we will see how this is done in 6 steps.
Step 1. We download and install the “dnsmasq
” package from the “yum repository” defined in our operating system
1 | # yum install dnsmasq |
Step 2. We start our Dnsmasq service and make the necessary settings to start automatically when your server is turned on.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | -- We run the command below to start our service. # service dnsmasq start -- When we start our service, if we get the error as below dnsmasq: failed to create listening socket: Address already in use -- We can use the commands below to fix this. # killall -9 dnsmasq # service dnsmasq start -- We can use the command below to start our service automatically when opening our server. # chkconfig dnsmasq on |
Step 3. If it is necessary to start, stop and restart our Dnsmasq
service, we can use the commands below.
1 2 3 4 5 6 7 8 9 10 | -- The command to use to start our service. # service dnsmasq start -- The command to use to stop our service. # service dnsmasq stop --The command to use to restart our service. # service dnsmasq restart |
Step 4. If the “firewall
” service is turned on in our server, we give the required permissions with the necessary commands and the desired permissions by the following commands. If our “firewall
” service is off then we do not need to take any action.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | -- The command to be used if we want to close our firewall service completely. -- We stop our service. # service iptables stop -- We turn off our service so that our server does not start automatically when opening. # chkconfig iptables off -- If your firewall service will remain active, we make the following settings. # iptables -I INPUT -p tcp --dport 53 -j ACCEPT # iptables -I INPUT -p udp --dport 53 -j ACCEPT # service iptables save # firewall-cmd --zone=public --add-port=53/tcp # firewall-cmd --zone=public --add-port=53/udp # firewall-cmd --permanent --zone=public --add-port=53/tcp # firewall-cmd --permanent --zone=public --add-port=53/udp |
Step 5. You can use two different configuration files for your Dnsmasq
configuration. The choice of this is up to you. Configuration files are given below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | -- We can find the "dnsmasq" configuration settings in our server in the file below. # vim /etc/dnsmasq.conf -- We will use the "hosts" file for name resolution on our server. In this file, we enter the server ip addresses and names locally. # vim /etc/hosts # RAC IP Address # Public 192.168.2.121 tchsftcntrac1.localdomain tchsftcntrac1 192.168.2.122 tchsftcntrac2.localdomain tchsftcntrac2 # Virtual 192.168.2.131 tchsftcntrac1-vip.localdomain tchsftcntrac1-vip 192.168.2.132 tchsftcntrac2-vip.localdomain tchsftcntrac2-vip # Private 192.168.117.141 tchsftcntrac1-priv.localdomain tchsftcntrac1-priv 192.168.117.143 tchsftcntrac1-priv2.localdomain tchsftcntrac1-priv2 192.168.117.142 tchsftcntrac2-priv.localdomain tchsftcntrac2-priv 192.168.117.144 tchsftcntrac2-priv2.localdomain tchsftcntrac2-priv2 # Scan IP 192.168.2.125 tchsftcntrac-scan.localdomain tchsftcntrac-scan 192.168.2.126 tchsftcntrac-scan.localdomain tchsftcntrac-scan 192.168.2.127 tchsftcntrac-scan.localdomain tchsftcntrac-scan # Server IP Address # File Server 192.168.2.130 techsoftcenter-fs.localdomain techsoftcenter-fs |
Step 6. We need to enter the address of the server that we configure “dnsmasq
” in the “/etc/resolv.conf
” file on the servers or computers that will do name resolution.
1 2 3 4 5 6 7 8 | -- In order for our servers and clients to perform name resolution, we enter the IP address of our server where we run the "dnsmasq" service in the "resolv.conf" file. # vim /etc/resolv.conf # Generated by NetworkManager search localdomain nameserver 192.168.2.120 |
In this article, we have seen “Basic DNS Configuration in Linux Operating Systems. If you want to install a more detailed DNS server,“ How to Configure DNS and DHCP Server on Linux Operating Systems? ” you can review our article.
I hope it was a useful article.