org.opennms.netmgt.poller.monitors
Class DnsMonitor

java.lang.Object
  org.opennms.netmgt.poller.monitors.IPv4Monitor
      org.opennms.netmgt.poller.monitors.DnsMonitor

All Implemented Interfaces:

ServiceMonitor

@Distributable
public final class DnsMonitor
extends IPv4Monitor

This class is designed to be used by the service poller framework to test the availability of the DNS service on remote interfaces. The class implements the ServiceMonitor interface that allows it to be used along with other plug-ins by the service poller framework.

Author:

Tarus Balog , OpenNMS

Constructor Summary

DnsMonitor()

Method Summary

PollStatus

poll(MonitoredService svc, Map parameters) Poll the specified address for DNS service availability.

Methods inherited from class org.opennms.netmgt.poller.monitors.IPv4Monitor

initialize, initialize, log, logDown, logDown, logUp, release, release

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DnsMonitor

public DnsMonitor()

Method Detail

poll

public PollStatus poll(MonitoredService svc,
                       Map parameters)

Poll the specified address for DNS service availability.

During the poll an DNS address request query packet is generated for hostname 'localhost'. The query is sent via UDP socket to the interface at the specified port (by default UDP port 53). If a response is received, it is parsed and validated. If the DNS lookup was successful the service status is set to SERVICE_AVAILABLE and the method returns.

Specified by:

poll in interface ServiceMonitor

Specified by:

poll in class IPv4Monitor

Parameters:

parameters - The package parameters (timeout, retry, etc...) to be used for this poll.

iface - The network interface to test the service on.

Returns:

The availibility of the interface and if a transition event should be supressed.

See Also:

PollStatus.SERVICE_AVAILABLE, PollStatus.SERVICE_UNAVAILABLE