Sometimes it’s useful to block outbound connections to a certain host. For example, when testing how your locally-running code reacts when a service it depends on or calls goes down.
To block outgoing connections to a given host, say:
api.zention.co.uk, edit the hosts file with
sudo vi /private/etc/hosts and add a line like this:
Then flush the DNS cache so the hosts file is re-read:
You can then test the code which calls the service as your Mac will no longer be able to connect to that host.
When you have finished, you can re-enable outbound connections to that host by removing the line and re-flushing the DNS cache again.