Mackerel Support About monitoring Mackerel's specs How do the Mackerel and the mackerel-agent communicate? mackerel -agent communicates with the Mackerel via its HTTP REST API. No direct communication is done from the Mackerel side to the host that contains mackerel-agent. Encrypted with SSL/TLS correspondence. Related articles What is Mackerel's IP address and port number? Is it possible to monitor network devices? How can I stay up to date on Mackerel’s ongoing development? I want to restrict access to an organization by specifying an IP address An unexpected error message occurs with Windows event log monitoring.