Tag Archives: DNS

Build an openDNS recursive resolver DNS using Bind

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It’s a small thing, but someone might feel it to be useful of running a public DNS like google has 8.8.8.8. You actually can build a recursive DNS and serve to the world (instead to your network user only! 🙂 )

Install Bind

apt install bind9 bind9utils -y

It’s pretty simple, all you need is the have your bind package installed and some very basic configurations like below-

nano /etc/bind/named.conf
include "/etc/bind/named.conf.options";
include "/etc/bind/named.conf.local";
include "/etc/bind/named.conf.default-zones";
nano /etc/bind/named.conf.options

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DNS Slave Using Virtualmin

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DNS Slave Auto-Configuration Quickstart

A quick guide to assist administrators who want to use Virtualmin’s automatic DNS slave configuration features. This allows for DNS server redundancy.

Introduction

Virtualmin can automatically manage any number of DNS slave servers for you. Once configured, it will create slave zones on other servers and configure them to automatically update when changes are made on your Virtualmin server. For this to work, you need Virtualmin on your primary server and Webmin (a free download) on your slave server(s). Henceforth, all references will refer to the primary server as the “Virtualmin server” and the DNS slave server as the “slave server”.

Getting Webmin for the Slave

If you don’t have Virtualmin installed on your slave server(s), you’ll need to install Webmin. Webmin is available for nearly every UNIX and Linux variant available, and is free to download and use. Continue reading “DNS Slave Using Virtualmin” »

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Vesta- How to set up master-slave DNS cluster

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If you are looking for the options to avoid any DNS-related downtime or the way to manage dns across all server you have, you might consider to set up dns cluster.

Create user dns-cluster on a server which will be used as dns slave

On the second server (slave) with vestacp you should create new user with name dns-cluster (via gui or cli)Code: 

v-add-user dns-cluster passowrd yourmail@example.tld

On the first server (master) you should run this command: Continue reading “Vesta- How to set up master-slave DNS cluster” »

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DNS Forwarder and Transfer using Bind and Webmin

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To point your BIND based DNS server to use OpenDNS resolvers for external resolution you need to modify the named.conf.options and add the OpenDNS resolvers as forwarders. This can be done in two ways:

via the command line, Shell\SSH
via a GUI if you have Webmin installed on your BIND server

Shell\SSH Instructions

Attach directly to your server or ssh to it. From there, go into /etc/bind/.  This is the default location so you may need to change this based on your configuration.

From there you will need to edit named.conf.options with your favorite text editor. Continue reading “DNS Forwarder and Transfer using Bind and Webmin” »

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Test your DNS using Dig, Nmap, Tcpdump

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For DNS resolution to succeed to 192.168.0.1, the DNS server at 192.168.0.1 will need to accept TCP and UDP traffic over port 53 from our server. A port scanner such as the nmap tool can be used to confirm if the DNS server is available on port 53 as shown below.

Note: To install nmap run ‘yum install nmap -y’.

[root@centos ~]# nmap -sU -p 53 192.168.0.1
Starting Nmap 6.40 ( http://nmap.org ) at 2015-08-26 15:22 AEST
Nmap scan report for 192.168.0.1
Host is up (0.00091s latency).
PORT STATE SERVICE
53/udp open|filtered domain
MAC Address: 02:00:79:55:00:0D (Unknown)
Nmap done: 1 IP address (1 host up) scanned in 0.29 seconds

[root@centos ~]# nmap -sT -p 53 192.168.0.1
Starting Nmap 6.40 ( http://nmap.org ) at 2015-08-26 15:22 AEST
Nmap scan report for 192.168.0.1
Host is up (0.00099s latency).
PORT STATE SERVICE
53/tcp open domain
MAC Address: 02:00:79:55:00:0D (Unknown)
Nmap done: 1 IP address (1 host up) scanned in 0.07 seconds

Continue reading “Test your DNS using Dig, Nmap, Tcpdump” »

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