From OpenNMS

org.opennms.core.utils.useJMTA=false
org.opennms.core.utils.transport=smtp
org.opennms.core.utils.mailHost=smtp.gmail.com
org.opennms.core.utils.smtpport=587
org.opennms.core.utils.smtpssl.enable=false
org.opennms.core.utils.authenticate=true
org.opennms.core.utils.authenticateUser=foo@gmail.com
org.opennms.core.utils.authenticatePassword=pass4foo
org.opennms.core.utils.starttls.enable=true
org.opennms.core.utils.messageContentType=text/html
org.opennms.core.utils.charset=UTF-8

Note:

• This works as of 5/7/2008 and is different than the settings in etc/examples/javamail-configuration.properties as of build 1.5.91-SNAPSHOT.
• These lines are found in etc/examples/javamail-configuration.properties for a gmail account, but are modified above:

org.opennms.core.utils.transport=smtps
org.opennms.core.utils.smtpport=465
org.opennms.core.utils.smtpssl.enable=true