SmtpMonitor The SMTP monitor tests for SMTP service availability on a node. The monitor first tries to establish a TCP connection on the specified port. If it establishes a connection, the service banner is checked for a valid response (starts with 220). If the banner is valid, the monitor sends a HELO SMTP command, identifying itself with the hostname of the OpenNMS server, and makes sure the service answers with a valid response (starts with 250). If that response to the HELO is valid, the monitor issues a QUIT SMTP command. The service is considered available if the service’s answer to the HELO command is valid (starts with 221). Simulate the behavior with telnet or netcat: $ nc -v gmail-smtp-in.l.google.com 25 Ncat: Version 7.60 ( https://nmap.org/ncat ) Ncat: Connected to 2607:f8b0:4002:c06::1a:25. 220 mx.google.com ESMTP j17-v6si13545102ywb.87 - gsmtp HELO opennms.com 250 mx.google.com at your service QUIT 221 2.0.0 closing connection j17-v6si13545102ywb.87 - gsmtp Monitor facts Class Name org.opennms.netmgt.poller.monitors.SmtpMonitor Configuration and use Table 1. Optional monitor-specific parameters for the SmtpMonitor Parameter Description Default port TCP port to connect to. 25 retry Number of attempts to find the service available. 0 Examples The following example uses CentOS/RHEL path names. For Debian/Ubuntu, use /var/lib/opennms/rrd/response. <service name="SMTP" interval="300000" user-defined="false" status="on"> <parameter key="retry" value="1" /> <parameter key="timeout" value="3000" /> <parameter key="port" value="25" /> <parameter key="rrd-repository" value="/opt/opennms/share/rrd/response" /> <parameter key="rrd-base-name" value="smtp" /> <parameter key="ds-name" value="smtp" /> </service> <monitor service="SMTP" class-name="org.opennms.netmgt.poller.monitors.SmtpMonitor" /> SmbMonitor SnmpMonitor