Monitoring the status of NetLinks

To monitor the status of the links, define the probe IP addresses in the NetLink properties.

The Engine sends ICMP messages to make sure that a link is still available. Only NetLinks that are used in an Outbound Multi-Link element are probed. Status monitoring is not available for NetLinks that are only used in Routing.

Probing is always recommended, and it is mandatory with the following features:

• The ratio-based load-balancing method
• Fail over to standby NetLinks
• Inbound traffic balancing with dynamic DNS updates

Ensure that the selected Probe IP Addresses provide a reliable measurement of link performance. For example, probing the IP address of an ADSL router may succeed even if the ISP network is unreachable. Similarly, probing the ISP-provided default gateway may succeed even if the ISP cannot forward traffic outside its own network.

To avoid probing failures caused by a probed host going down, add several alternative Probe IP Addresses.