Operation and Configuration Guide 3.14
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A.3 WAN Link Configuration Settings
For a Wide Area Network (WAN), the oMG supports three types of network
interfaces: cellular, WiFi and Ethernet. The following subsections describe the
configuration settings for each type.
A.3.1 Cellular WAN Link Configuration Settings
•
High Cost Link
: Defines this link as High Cost, limiting the frequency and
amount of management data sent over the link. During initial testing avoid
enabling this feature to ensure all management events are emitted. If data
plan costs are a concern, enable this after the oMG is put into operation.
•
Change Default MTU Size
: May be required to accommodate some network
configurations. Only change if advised by Sierra Wireless. Default is disabled.
•
Auto Local IP
: Enables DHCP for this interface. The IP address will be
assigned by a DHCP server connected to the access point network. For most
applications, the IP addresses should be obtained automatically from the
network.
•
Local IP Address
: Specifies the static IP address if Auto Local IP is disabled.
•
Masquerade
: This enables Network Address Translation for all LAN-origi-
nated traffic leaving the oMG WAN interface. This is almost always a
mandatory setting. Many Mobile Network Operators will disconnect a cellular
modem that emits IP datagrams which bear an address other than that of the
cellular modem.
•
Masquerade Port Range
: Auto/Manual—manual is the default and should be
used in most cases to avoid using “defined” or “reserved” ports.
·
Minimum/Maximum Port Number
: The range of ports to use for
masquerade. The default range is: 49152 to 65535. The minimum value
is 0 and the maximum is 65535. If the minimum is set below 49152:
traffic on ports lower than 512 are mapped to other ports lower than 512.
traffic on ports 512 to 1024 are mapped to ports lower than 1024.
traffic on ports greater than 1024 are mapped to ports greater than 1024.
•
Automatic DNS
: if selected, the DNS servers provided by the network
service provider (via DHCP) will be used to resolve host names.
If Automatic DNS is not selected, specific DNS server IP addresses can be
specified in the Primary DNS and Secondary DNS fields. All servers are con-
sidered as a group that optimizes DNS response time. The initial host name
resolution request is broadcast to all these servers and the one with the fast-
est response time is selected for future requests.
When a DNS resolution request times out, another broadcast is sent to all
DNS servers, and occasional DNS broadcasts are made to ensure the current
server is still the fastest.
Note: This forwarder optimization mechanism can create resolution issues when
VPNS are used in conjunction with internal DNS servers. This requires DNS zones to
be defined on the oMG—see
Configuring DNS Zones for Private DNS Server Use
page 43 for details.