D-Link NetDefendOS, User Manual

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problem. With a single host, it either responds or it doesn't so the
50% rule is not relevant.
A host is not used in this 50% calculation until NetDefendOS has
been able to reach it at least once since the last NetDefendOS
reconfiguration or full restart. This means that an unreachable
host can be responsible for triggering an action once but not
twice.
A group of three hosts, where one has been unreachable since
the last reconfiguration, will therefore be treated as a two-host
group until the third becomes reachable. This also means that if a
problem triggers an action and the problem is not solved,
NetDefendOS will not attempt to repeat the same action until the
problem is solved and the hosts are again reachable.
Max Loss A single host is considered unreachable if this number of
consecutive ping responses to that host are not replied to. The
default value is 7.
Initial Grace Period Do not allow the link monitor to trigger an action for this number
of seconds after the last reconfiguration. This avoids false
positives during initial link negotiation. The default value is 45
seconds.
Ping Interval The number of milliseconds between pings sent to hosts. The
default value is 250.
Routing Table This is the routing table used for looking up the route for the host
IP addresses. The default is the
main routing table.
Use Shared IP This is only used when monitoring in a HA cluster. It allows the
link monitor pings to be sent from the shared IP address instead
of sending using the individual IPs of each unit. This is useful if
public IPv4 addresses are not available for each unit in the cluster.
See also
Section 11.6, “Link Monitoring and HA” .
Example 2.32. Link Monitor Setup
This example creates a Link Monitor object that will monitor the availability of the host found at
the IPv4 address my_host . It is assumed this IPv4 address is already defined in the NetDefendOS
address book.
The action for the monitor is HA Failover if it detects that the host is unavailable.
Command-Line Interface
gw-world:/> add LinkMonitor Action=HAFailover Addresses=my_host
Web Interface
1. Go to: System > Device > Link Monitors > Add > Link Monitor
2. Enter the following:
• Action: HA Failover
Chapter 2: Management and Maintenance
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