This doc outlines how to check and troubleshoot connectivity from the Access Tier (aka netagent) to a backend server.
There is a convenient built in way to test connectivity to backend servers on the Command Center under Managed Services on a per service level. Select either the Hosted Websites or Infrastructure service and select the Service Name. In the top right corner there is a button called Test Connection. This will perform 4 tests and give a status of green for pass or red for fail. This article is focused on the connectivity between the Access Tier and the backend server.
Backend Hostname or IP is resolvable
Backend host and port are reachable from access tier
This test performs a TCP connection from the Access Tier to the backend server on the port specified in the service configuration.
Brief description of how to confirm the problem is solved and what to do if it isn’t
Links to related articles