We use OpenNMS to monitor services such as SMTP and HTTP on our Mailman server. OpenNMS logs issues throughout the night (every 20 minutes apart) that "SMTP outage identified on interface Ethernet 1 with reason code: Did not receive expected response within timeout timeout: 3000ms retry: 1 of 1."
What is the reasonable response time for Mailman SMTP? Any other factors that may affect the response time? We never receive these errors before, just starting last night.