No, there are two ways, configuring the DNS server OR use the clients hosts file.
I use the DNS server configuration method but for just a quick test I recommend to edit the hosts file on the client.
With both methods the client is able to resolve the IP out of a name, so you can test a named reverse proxy in the client browser.
EDIT:
I think I misunderstood…
On the other Nethserver I use the server manager (System/DNS) to add the entries and the template system writes the /etc/hosts file.