The Internet runs mostly on ISC’s BIND DNS server. In this artcile I will explain how to setup a simple BIND server on a Linux box.
The basic steps involved in setting up BIND are:
– Download BIND from ISC’s website
When downloading BIND, you might be better off if you pick an ESV, or an extended support version. As of the writing of this article, 9.9.5 is the latest ESV.
ESV versions are supported for at least 3 years by ISC. You can check the latest ESV version here https://www.isc.org/downloads/. If you are wondering as to why not to use the vendor provided BIND version, it’s because the vendor may not be using the ESV version, and may also lag behind in patches. Using the latest ESV from BIND will get you the most stable version for production use.
– Compile BIND
You will need gcc, make to compile bind. You can run ‘sudo yum groupinstall “Development Tools” -y’ on your CentOS or RedHat box to install GCC. In order to compile BIND, after downloading it, untar it, and then try the following from the directory you have untarred the distriution in.
$sudo yum groupinstall "Development Tools" -y $./configure --prefix=/opt/bind-9.9.5 --enable-newstats --with-libxml2 $make #make install
The above will install BIND in /opt/bind-9.9.5, after that you can link /opt/bind to /opt/bind-9.9.5 with “sudo ln -s /opt/bind-9.9.5 /opt/bind”.
I have enabled newstats and with libxml because this allows me to view BIND query stats in a format which I find easy to use.
– Configure a master server
Now that you have downloaded BIND, and compiled it, as well as installed it, we will move onto configuring it. The basic steps in configuration are as follows:
I have placed extensive comments in the conf file and in the zone files, please review them in order to understand what information to place in the files
A. Create a named.conf zone file in etc dire of chroot. See https://github.com/syedaali/configs/blob/master/bind-master-named.conf for a sample with comments.
B. Install a root hints file, example is here https://github.com/syedaali/configs/blob/master/bind-root.hints.
C. Create a forward lookup zone file, sample is here https://github.com/syedaali/configs/blob/master/bind-example.com.zone.
D. Create a reverse lookup zone file, sample is here https://github.com/syedaali/configs/blob/master/bind-10.1.1.rev.
E. Create a loopback forward and reverse zone. Forward sample is here https://github.com/syedaali/configs/blob/master/bind-master.localhost.
Sample of reverse lookup for localhost is here https://github.com/syedaali/configs/blob/master/bind-127.0.0.rev.
– Install one slave server
A. Compile BIND as seen in above steps for master
B. Install BIND in /opt/bind-9.9.5
C. Link to /opt/bin
D. Repeat steps B through E from master, with the exception that in the zone file, specify slave instead of master.
Sample slave zone file is here https://github.com/syedaali/configs/blob/master/bind-slave-named.conf.
– Configure your clients to point to the slave server
It is generally a good idea to avoid pointing your BIND clients to the BIND master. Instead create two slaves, and point the clients to the slaves. For instance if your master has IP address 10.1.1.10, and you have two BIND slaves, with IP 10.1.1.11 and 10.1.1.12, then in your clients /etc/resolv.conf do the following:
$cat /etc/resolv.conf domain example.com nameserver 10.1.1.11 nameserver 10.1.1.2
In future blogs I will specify how to monitor BIND. Do share your experience with BIND setup here.