Digi IX20, Руководство пользователя

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Interfaces Wide Area Networks (WANs)
IX20 User Guide 53
Note If your device is operating on a private APN or on wired network with firewall restrictions,
ensure that the DNS servers on your private network allow DNS lookups for
my.devicecloud.com; otherwise, the SureLink DNS query test will fail and the IX20 device will
determine that the interface is down.
By default, these tests will be performed every 15 minutes, with a response timeout of 15 seconds. If
the tests fail three consecutive times, the device will reset the network interface to attempt to
recover the connection.
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 IX20 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 IX20 device to regularly probe connections through the WAN
to determine if the WAN has failed.
Required configuration items
n
Enable SureLink.
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.
n
The type of probe test to be performed, either:
l
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
configured for the WAN.
l
HTTP or HTTPS test: Requires the URL of the host to be tested.
l
Interface status: Determines if the interface has an IP address assigned to it, that the
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
n
The behavior of the IX20 device upon test failure:
l
The default behavior, which is to fail over to the next priority WAN/WWAN.
l
Restart the WAN interface.
l
Reboot the device.
n
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
considering it to have failed.
n
If the type of probe test is:
l
Ping: Configure the number of bytes in the ping packet.