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 a connection is established, a service banner should have been received. The monitor makes sure the service banner is a valid SMTP banner (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 the 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").

The behaviour can be simulated 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

Remote Enabled

true

Configuration and Use

Table 1. Monitor specific parameters for the SmtpMonitor
Parameter	Description	Required	Default value
`port`	TCP port to connect to.	optional	`25`
`retry`	Number of attempts to find the service available.	optional	`0`
`timeout`	Timeout in milliseconds for the underlying socket’s connect and read operations.	optional	`3000`

Examples

<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="${install.share.dir}/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" />