Transparent Mode Scenarios; Transparent Mode Scenario 1 - D-Link NetDefend DFL-210 User Manual

4.7.3. Transparent Mode Scenarios

Route type
Switch
Switch
Non-switch
Non-switch
The appropriate IP rules will also need to be added to the IP rule set to allow Internet access through
the NetDefend Firewall.
Grouping IP Addresses
It can be quicker when dealing with many IP addresses to group all the addresses into a single group
IP object and then use that object in a single defined route. In the above example, 85.12.184.39 and
194.142.215.15 could be grouped into a single object in this way.
Using NAT
NAT should not be enabled for NetDefendOS in Transparent Mode since, as explained previously,
the NetDefend Firewall is acting like a level 2 switch and address translation is done at the higher IP
OSI layer.
The other consequence of not using NAT is that IP addresses of users accessing the Internet usually
need to be public IP addresses.
If NATing needs to be performed in the example above to hide individual addresses from the
Internet, it would have to be done by a device (possibly another NetDefend Firewall) between the
192.168.10.0/24 network and the public Internet. In this case, internal IP addresses could be used by
the users on Ethernet network pn2.
4.7.3. Transparent Mode Scenarios
Scenario 1
The firewall in Transparent Mode is placed between an Internet access router and the internal
network. The router is used to share the Internet connection with a single public IP address. The
internal NATed network behind the firewall is in the 10.0.0.0/24 address space. Clients on the
internal network are allowed to access the Internet via the HTTP protocol.
Figure 4.15. Transparent Mode Scenario 1
Interface Destination
if1
if2
if1 85.12.184.39
if1 194.142.215.15
183
Chapter 4. Routing
Gateway
all-nets
all-nets
gw-ip
gw-ip