tcp

// The number of established TCP connections of a Linux host, by SNMP, from tcpCurrEstab (TCP-MIB):
// those in the ESTABLISHED or CLOSE-WAIT state.
need('protocol:snmp');

output('established', 'number', array('label' => 'Established connections'));

// No default threshold: what is normal depends on the server's role.
watch.above('too-many', 'Too many TCP connections', 'established', array('enabled' => false));
watch.habit('unusual', 'Unusual number of connections', 'established', array('enabled' => false));

value('established', snmp.get('1.3.6.1.2.1.6.9.0'));