User`s guide

Configuration through the web interface
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 TCP Connection Test: Enables or disables the creation of a new TCP connection as a
test to verify the integrity of the mobile connection. The test is successful if a TCP
connection is established to a specified remote host and port number. If the remote host
actively refuses the connection request, the test is also considered to be successful, since
that demonstrates successful two-way communication over the mobile connection. The
TCP connection test waits up to 30 seconds for the connection to be established or
refused. When the TCP connection is established, the test completes successfully, and
the TCP connection is closed immediately.
Two destination hosts may be configured for this test. If the first host fails to establish
(or refuse) the TCP connection, the same test is attempted to the second host. If neither
host successfully establishes (or refuses) the TCP connection, the test fails. The primary
and secondary addresses may be either IP addresses or fully qualified domain names.
– TCP Port: The TCP port number to connect to on the remote host (default 80).
– Primary Address: The address of the first host to test.
– Secondary Address: The address of the second host to test (if the first host fails).
 DNS Lookup Test: Enables or disables the use of a Domain Name Server (DNS)
lookup as a test to verify the integrity of the mobile connection. The test is successful if
a valid reply is received from a DNS server. Typically, this means the hostname is
successfully “resolved” to an IP address by a DNS server. But even a reply such as “not
found” or “name does not exist” is acceptable as a successful test result, since that
demonstrates successful two-way communication over the mobile connection. When a
valid reply is received, the test completes successfully and immediately.
The DNS servers used in this test for the hostname lookup, are the primary and
secondary DNS servers obtained from the mobile network when the mobile PPP
connection is first established. These addresses can be viewed by going to
Administration > System Information > Mobile.
Note that this DNS test is independent of the normal DNS client configuration and
lookup cache, which is used for other hostname lookups. This test has been specifically
designed to require communication over the mobile connection for each lookup, and to
avoid being “short-circuited” by previously cached information. Also, this test does not
interfere in any way with the normal DNS client configuration of this device.
Two hostnames may be configured for this test. If the first hostname fails to get a reply,
the same test is attempted for the second hostname. If no reply is received for either
hostname, the test fails. The primary and secondary DNS names should be fully
qualified domain names. Note that the reverse lookup of an IP address is possible, but
that is usually unlikely to succeed in returning a name. Still, such a reverse lookup can
be used to demonstrate the integrity of the mobile connection.
– Primary DNS Name: The first hostname to look up.
– Secondary DNS Name: The second hostname to look up (if the first hostname fails).
 Repeat the selected link integrity test every N seconds: Specifies the interval, in
seconds, at which the selected test is initiated (repeated). A new test will be started
every N seconds while the mobile connection is established. This value must be between
10 and 65535. The default is 240.
If the configured interval is less time than it takes a test to complete, the next test will
not be initiated until the previous (current) test has completed.