For the average consumer client device like a laptop or ipad, this is normally fine.It is unlikely that other devices on the network want to communicate with the laptop using a hostname.
Under the covers, they use DHCP to get an available IP address from your DHCP server.
Synology can host both of these services and they both work well by themselves. They both deal with IP addresses and hostnames, yet they operate independently.
For example, when you power on your laptop, the laptop will essentially say something like this: "Hello, my hostname is and I need an available IP address".
The DHCP server will gladly assign an unused IP address, but that is where things end.
The DNS server knows nothing about this hostname to IP address assignment.
This means that no other host on the network will be able to refer to the laptop if they only know the hostname.
You can't, for example, do something like from another host on your network.
Scripts that help with Synology Diskstation maintenance You are running Synology Diskstation DNS and DHCP services and you want dynamic DHCP reservations to update DNS immediately.
Synology Diskstation has an embedded DNS server that can be enabled for your network.
This does the standard thing of resolving hostnames to IP addresses.
So, lets say you have a VMware ESXi server on your local network. Only the DNS server needs to remember the IP address. Synology diskstation also has a DHCP server that you can use to dynamically assign IP addreses to hosts on your network.