Digi TransPort WR11 User Manual page 260

Configuring network interfaces
IP address and Port
Enable Network Address and Port Translation (NAPT).
This mode behaves like NAT but in addition to changing the source IP of the packet from the
private host it can also change the source port number. This is required if more than one
private host attempts to connect using the same local port number to the same Internet host
on the same remote port number. If such a scenario were to occur with NAT the router would
be unable to determine which private host to route the returning packets to and the
connection would fail.
NAT Source IP address
If specified, and NAT mode is set to NAT or NATP for this interface, then the source address of
packets being sent out this interface is changed to this address, rather than the interface
address.
Enable IPsec on this interface
The IPSec parameter enables or disables IPSec processing on this interface. If this box is
checked, packets sent or received on this interface must pass through the IPSec code before
being transmitted. IPSec may drop the packet, pass it unchanged, or encrypt and encapsulate
within an IPSec packet.
Keep Security Associations (SAs) when this Mobile interface is disconnected
Configures the router to keep any existing IKE and IPsec associations should the link drop. This
is usually applied on head-end routers with fixed IP addresses.
Use interface X, Y for the source IP address of IPsec packets
By default, the source IP address for an IPSec Eroute is the IP address of the interface on
which IPSec was enabled. By setting this parameter to either a PPP or Ethernet interface, the
source IP address IPSec uses will match that of the Ethernet or PPP interface specified.
Enable the firewall on this interface
Turns Firewall script processing On or Off for this interface. If the firewall is enabled on an
interface and with the absence of any firewall rules, the default action is to block ALL traffic. To
configure the firewall, see the
Limit the data transmitted over this interface
On W-WAN networks (where charging is based on the amount of data transferred as opposed
to time spent on-line), this parameter specifies a data limit after which the router will create
an entry in the event log to indicate that this amount of data has been transferred. For
example, if your monthly tariff includes up to 5 MB of data before you are charged an excess,
you might set the Data limit warning level to 4000. This would cause the router to place a
warning entry in the event log once you had transferred 4 MB. You could use this event to
trigger an email alert message, SNMP trap or SMS alert message.
Issue a warning event after
The maximum data to be transmitted before a warning entry is generated in the Event Log.
You can select kilobytes, megabytes or gigabytes via the drop-down box.
Digi TransPort® Routers User Guide
Firewall section.
Configure DSL interfaces
260