I’m not sure what you mean by Server.
You have only Agent - piece of software that running on the node. It collects metrics and it also display dashboards when you go to
You can change behaviour of web part of the agent, by doing changes to agent configs.
Netdata cloud is not using HTTP access(over port 19999), it communicates with Agent over websockets. So, if you only want to using Netdata Cloud, you can disable web part on your agent and check all data from Netdata Cloud.
If you have multiple netdata nodes and don’t use Netdata Cloud - you can set up one parent node, disable web on all child nodes, stream all metrics from child nodes to parent node.
Then secure that parent node with Ngnix or Apache with basic auth, for example.