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Interfaces
Configure SureLink active recovery to detect WAN/WWAN failures
Problems can occur beyond the immediate WAN/WWAN connection that prevent some IP traffic from
reaching its destination. Normally this kind of problem does not cause the Connect EZ device to
detect that the WAN has failed, because the connection continues to work while the core problem
exists somewhere else in the network.
Using Digi SureLink, you can configure the Connect EZ device to regularly probe connections through
the WAN to determine if the WAN has failed.
Required configuration items
Enable SureLink.
n
SureLink can be enabled for both IPv4 and IPv6 configurations. By default, SureLink is enabled
for IPv4 for the preconfigured WAN (ETH1) and WWAN (Modem). It is disabled for IPv6.
When SureLink is configured for Wireless WANs, SureLink tests are only run if the cellular
modem is connected and has an IP address. Use the SIM failover options to configure the
Connect EZ device to automatically recover the modem in the event that it cannot obtain an IP
address. See
The type of probe test to be performed, one of:
n
Test another interface's status: Used to create a failover or coupled relationship between
l
two interfaces. Requires the name of the alternate interface, the IP version to be tested,
and the expected status of the alternate interface (either up or down).
Ping: Requires the hostname or IP address of the host to be pinged.
l
DNS query: You can perform a DNS query to a named DNS server, or to the DNS servers
l
configured for the WAN.
HTTP test: Requires the URL of the host to be tested.
l
Test DNS servers configured for this interface: Tests communication with this interface's
l
DNS servers that are either provided by DHCP, or statically configured.
Interface status: Determines if the interface has an IP address assigned to it, that the
l
physical link is up, and that a route is present to send traffic out of the network interface.
The preconfigured WAN is configured by default to use SureLink to both test the interface
status and perform a test DNS query.
Additional configuration items
The behavior of the Connect EZ device upon test failure:
n
The default behavior, which is to restart the interface and fail over to the next priority
l
WAN/WWAN.
For WWANs, SIM switching (also enabled by default).
l
For WWANs, reset the modem.
l
Reboot the device.
l
The interval between connectivity tests.
n
The number of probe attempts before the WAN is considered to have failed.
n
The amount of time that the device should wait for a response to a probe attempt before
n
considering it to have failed.
Digi Connect EZ 4/4i User Guide
Configure a Wireless Wide Area Network (WWAN)
Wide Area Networks (WANs)
for details about SIM failover.
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