Installing DNS on a Synology NAS

Firstly, why am i doing this?

So I have a VMware Homelab environment and DNS is a very important part of a VMware environment. I've been through a couple of iterations of my Homelab, and in both cases I built an Ubuntu VM running BIND DNS on my VMware Homelab. the problem with this is the DNS VM is dependant on the VMware lab itself, so i needed a better way of doing this.

On speaking to a fellow colleague, I realized it would be better to move DNS so it is external to my homelab environment. There are various ways you can do this, which i won't go into here, but as i already have a Synology NAS, i decided to use the extended features of this smart NAS to see how it would fare as a DNS server.

The following steps document installing and configuring DNS on a Synology NAS DS416J. I would assume the steps for other Synology models are similar.

For reference the official Synology guide for setting up DNS can be found here

Pre-requisites

This guide assumes you have at least a basic working understanding of DNS and that you know how to configure it appropriate to your network. In my case, my home router is configured with the default address of 192.168.0.1, I have then configured it to use DHCP for about 100 address, with the remainder available for fixed IPs, which i'll create DNS records for. You can of course use different parts of the 192.168 address range, or other Private IP address ranges if you wish, as long as you configure your network settings appropriately. I have just kept things simple for this setup.

Installing the DNS Server package

• Launch Package Center on your Synology NAS

• You can either search for DNS Server, or sort the available packages by name and locate the DNS server package as highlighted below

• Click the install option below the package and the installation will begin

Once the installation finishes, click Open on the DNS Server package, and you will see the screen below

Click Resolution, then click Enable Resolution Service, ensure Enable Forwarders is selected and set Forwarder's 1 and 2 as required then click Apply. In my case Forwarder 1 is my home router IP

Additionally, I opted to lock my settings down a little by selecting Limit source IP service, then configuring my full 192.168.0.0 address range as being allowed to send recursive queries via my DNS server, as below

Click Zones, Click Create, then Click Primary Zone

Here I've set my domain name to homelab, which is just a name i plan to use internally. The Primary DNS server is set to the IP of the Synology itself. Configure the remaining settings as required. Whilst i've enabled Limit Zone Transfer and Limit Zone update, they are currently unconfigured in this example. Limit source IP service is set to a range of 192.168.0.0 with subnet 255.255.0.0

Create some forward DNS records

Now you can create your Resource Records. Select your new zone entry > Edit > Resource Record. Click create and select a record type. This will typically be an A record, otherwise choose as appropriate. Then enter the hostname and the IP address, and click save.

Here is my Forward DNS zone with some A records for my ESXi hosts

Create a Reverse DNS Zone

Now we need to create a Reverse DNS zone. A reverse DNS zone is where you store PTR records that allow a computer to resolve an IP address back to a fully qualified domain name.

• From the Zones section, click Create > Primary Zone > Domain Type = Reverse Zone

• If your range is 192.168.0.0/24 then set your Domain name to be 0.168.192 and leave the suffix set to .in-addr.arpa (for IPv4)

• Set Serial Format to Date (for easier reading)

• In the screenshot, i have enabled Limit source IP service and restricted the hosts to my subnet range (192.168.0.0 with subnet mask 255.255.0.0)

• Click Save

Create some reverse DNS records

• Click Zones, highlight the new reverse zone file, click Edit > Resource Record

• Click Create then click PTR (pointer) type

• In the name field simply enter the last octet of the record you wish to add. For example, to add a PTR record for 192.168.0.100, simply enter 100 in the Name field

• Now enter enter the fully qualified hostname into the Host field, like the example below, then click Save to add the record

Here is my reverse DNS zone with a couple of PTR records for my 2 x ESXi hosts

Add the new DNS server to your DNS Servers list

• From the start menu or a command prompt, open the Network Connections panel using the command ncpa.cpl

• Double click on your active network connection, click Properties, double click Internet protocol version 4, click advanced, click add, enter the IP address of the new DNS server, and move it to the top of your list like so

Perform some test DNS lookups

Open a command prompt and use nslookup to see if you can resolve your new DNS records.

Here you can see i've tested both a forward and reverse lookup on one of my new ESXi hosts and it resolves successfully. You can also see the server returning the result is the new DNS server.

That concludes the basics of setting up your Synology NAS as a DNS server. Obviously individual environments may differ so adjust your settings accordingly!