How To Configure BIND as a DNS Server

The aim is to setup two DNS servers:
Master DNS server – OpenWRT router -192.168.0.1 – FQDN: ns1.example.com
Slave DNS server – Debian server – 192.168.0.2 – FQDN: ns2.example.com
Web Server – 192.168.0.3 – FQDN: example.com

Setting the Hostname on the Name Servers
Install Bind on Both Name Servers
Configure the Master Bind Server
Configure the Slave Bind Server

1. Setting the hostname

Edit /etc/hosts file so it looks like this

127.0.0.1       localhost
192.168.0.1     ns1.example.com ns1

and for debian server:

127.0.0.1       localhost
192.168.0.2     ns2.example.com ns2

then edit the /etc/hostname so it looks like this:

ns1

and for debian box:

ns2

2. Instal BIND

On the OpenWRT router from the ssh run the following:
Uninstall preinstalled dnsmasq:

/etc/init.d/dnsmasq stop
opkg remove dnsmasq

then install BIND

opkg update
opkg install bind-server bind-tools

On a debian box run:

 sudo apt-get update
 sudo apt-get install bind9 bind9utils bind9-doc

3. Configure the Master Bind Server

On the OpenWRT box the bind directory structure is a bit different from the one on debian as there is only one file that holds all the config: /etc/bind/named.conf

We need to add few bits to it (highlighted in red)

// this section defines who is allow to submit queries to the server
acl goodclients {
        192.168.0.0/24;
        localhost;
        localnets;
};

options {
        directory "/tmp";

        recursion yes;
        allow-transfer { none; };

        dnssec-validation auto;

        auth-nxdomain no;    # conform to RFC1035
        listen-on-v6 { any; };
};

// prime the server with knowledge of the root servers
zone "." {
        type hint;
        file "/etc/bind/db.root";
};

// be authoritative for the localhost forward and reverse zones, and for
// broadcast zones as per RFC 1912

zone "localhost" {
        type master;
        file "/etc/bind/db.local";
};

zone "127.in-addr.arpa" {
        type master;
        file "/etc/bind/db.127";
};

zone "0.in-addr.arpa" {
        type master;
        file "/etc/bind/db.0";
};

zone "255.in-addr.arpa" {
        type master;
        file "/etc/bind/db.255";
};

// here we define our zones

zone "example.com" {
    type master;
    file "/etc/bind/zones/db.example.com";
    allow-transfer { 192.168.0.2; };
};

zone "0.168.192.in-addr.arpa" {
    type master;
    file "/etc/bind/zones/db.192.168.0";
    allow-transfer { 192.168.0.2; };
};

Create the Forward Zone File

In the /etc/bind folder create zones subfolder then create db.example.com file and paste this content:

$TTL 604800
@ IN SOA ns1.example.com. root.example.com. (
                        10 ; Serial
                    604800 ; Refresh
                     86400 ; Retry
                   2419200 ; Expire
                  604800 ) ; Negative Cache TTL
;

; Name servers
example.com. IN NS ns1.example.com.
example.com. IN NS ns2.example.com.

; A records for name servers
ns1 IN A 192.168.0.1
ns2 IN A 192.168.0.2

; Other A records
@         IN A 192.168.0.3
www       IN A 192.168.0.3
computer1 IN A 192.168.0.4
printer   IN A 192.168.0.5

IMPORTANT bit to remember here is to change the serial number each time this file is edited!

Create the Reverse Zone File

In /etc/bind/zones create file: db.192.168.0 and paste this content:

$TTL    604800
@       IN      SOA     example.com. admin.example.com. (
                 10       ; Serial
           604800         ; Refresh
            86400         ; Retry
          2419200         ; Expire
           604800 )       ; Negative Cache TTL
;

; Name servers
IN      NS      ns1.example.com.
IN      NS      ns2.example.com.

; PTR Records
1               IN      NS      ns1.example.com.
2               IN      NS      ns2.example.com.
3               IN      NS      www.example.com.
5               IN      NS      printer.example.com.
4               IN      NS      computer1.example.com.

Testing

named-checkconf /etc/bind/named.conf

If there is a problem with the config this will tell you where to look in the config file. If the config is fine there is no output.
Next we check our zones:

named-checkzone example.com /etc/bind/zones/db.example.com

If your file has no problems, it should tell you that it loaded the correct serial number and give the “OK” message;

zone example.com/IN: loaded serial 10
OK

then we do the same thing to the reverse lookup zone file.

if everthing is OK the we enable and start the BIND service:

/etc/init.d/named enable
/etc/init.d/named start

With the server running run this:

dig ANY intra @localhost

and if everything is setup correctly you should get something like this:

root@wrt:/etc/bind/zones# dig any example.com @localhost

; <<>> DiG 9.9.6-P1 <<>> any example.com @localhost
;; global options: +cmd
;; Got answer:
;; ->>HEADER<

Configure the Slave Bind Server

Configuring the Options File

Now on our debian box we edit the config file

nano /etc/bind/named.conf.options

Edit the options section so it looks like this:

options {
directory "/var/cache/bind";
recursion no;
allow-transfer { none; };

dnssec-validation auto;

auth-nxdomain no; # conform to RFC1035
listen-on-v6 { any; };
};

Save and close the file when you are finished.

Configuring the Local Configuration File

sudo nano /etc/bind/named.conf.local

We will create each of our zone specifications.

First, we will work on the forward zone:

zone "example.com" {
};

and edit it so it looks like this:

zone "example.com" {
type slave;
file "db.example.com";
masters { 192.168.0.1; };
};

This completes our forward zone setup.

We can use this same exact format to take care of our reverse zone config:

zone "0.168.192.in-addr.arpa" {
type slave;
file "db.192.168.0";
masters { 192.168.0.1; };
};

When you are finished, you can save and close the file.

To check that zone transfer was successful run:

sudo tail -f /var/log/syslog

That should have some entries to indicate that the zone files have been transferred correctly.

To configure DHCP follow here.

Good source of BIND config knowledge here.