|You can secure the communication between Oracle Management Service (OMS) and Oracle Management Agents (Management Agents) by configuring a proxy. A proxy is an application external to Enterprise Manager Cloud Control that acts as an intermediary for managing HTTP as well as HTTPS requests across network boundaries or firewalls. By using a proxy, you can expose only certain ports for communication, and thereby have a more secure and reliable communication between the OMS and the Management Agents.
You can configure one proxy for all Management Agents, one proxy for a set of Management Agents and none for the rest, or different proxies for different sets of Management Agents.
In addition, you can configure two or more proxies as redundant proxies to support high availability of the proxies configured for OMS and Management Agent communication. Under such circumstances, by default, the proxy that is up and running is selected for communication, regardless of the status of the other proxies. Before starting to communicate if a proxy is found to be inactive or down, then an alternate proxy configured for that Management Agent is selected. However, note that after the communication begins through a particular proxy, if that proxy turns inactive or shuts down, then no fallback mechanism is currently available to select an alternate proxy that is up and running.
NTLM-based Microsoft proxies are not supported. To enable access through such proxies, add all the available agent hosts to the Unauthenticated Sites Properties of the NTLM-based Microsoft proxy.
Local addresses of each OMS automatically bypass the proxy.