D-Link DFL-260 Product Manual - Page 212

Non-transparent Mode Internet Access, NetDefendOS May Also Need Internet Access - internet filtering content

Page 212 highlights

4.7.2. Enabling Internet Access Chapter 4. Routing Figure 4.18. Non-transparent Mode Internet Access The non-switch route usually needed to allow Internet access would be: Route type Non-switch Interface if1 Destination all-nets Gateway gw-ip Now lets suppose the NetDefend Firewall is to operate in transparent mode between the users and the ISP. The illustration below shows how, using switch routes, the NetDefend Firewall is set up to be transparent between the internal physical Ethernet network (pn2) and the Ethernet network to the ISP's gateway (pn1). The two Ethernet networks are treated as a single logical IP network in Transparent Mode with a common address range (in this example 192.168.10.0/24). Figure 4.19. Transparent Mode Internet Access In this situation, any "normal" non-switch all-nets routes in the routing table should be removed and replaced with an all-nets switch route (not doing this is a common mistake during setup). This switch route will allow traffic from the local users on Ethernet network pn2 to find the ISP gateway. These same users should also configure the Internet gateway on their local computers to be the ISPs gateway address. In non-transparent mode the user's gateway IP would be the NetDefend Firewall's IP address but in transparent mode the ISP's gateway is on the same logical IP network as the users and will therefore be gw-ip. NetDefendOS May Also Need Internet Access The NetDefend Firewall also needs to find the public Internet if it is to perform NetDefendOS functions such as DNS lookup, Web Content Filtering or Anti-Virus and IDP updating. To allow this, individual "normal" non-switch routes need to be set up in the routing table for each IP address specifying the interface which leads to the ISP and the ISPs gateway IP address. 212

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Figure 4.18. Non-transparent Mode Internet Access
The non-switch route usually needed to allow Internet access would be:
Route type
Interface
Destination
Gateway
Non-switch
if1
all-nets
gw-ip
Now lets suppose the NetDefend Firewall is to operate in transparent mode between the users and
the ISP. The illustration below shows how, using switch routes, the NetDefend Firewall is set up to
be transparent between the internal physical Ethernet network (
pn2
) and the Ethernet network to the
ISP's gateway (
pn1
). The two Ethernet networks are treated as a single logical IP network in
Transparent Mode with a common address range (in this example
192.168.10.0/24
).
Figure 4.19. Transparent Mode Internet Access
In this situation, any "normal" non-switch
all-nets
routes in the routing table should be removed and
replaced with an
all-nets
switch route (not doing this is a common mistake during setup). This
switch route will allow traffic from the local users on Ethernet network
pn2
to find the ISP gateway.
These same users should also configure the Internet gateway on their local computers to be the ISPs
gateway address. In non-transparent mode the user's gateway IP would be the NetDefend Firewall's
IP address but in transparent mode the ISP's gateway is on the same logical IP network as the users
and will therefore be
gw-ip
.
NetDefendOS May Also Need Internet Access
The NetDefend Firewall also needs to find the public Internet if it is to perform NetDefendOS
functions such as DNS lookup, Web Content Filtering or Anti-Virus and IDP updating. To allow
this, individual "normal" non-switch routes need to be set up in the routing table for each IP address
specifying the interface which leads to the ISP and the ISPs gateway IP address.
4.7.2. Enabling Internet Access
Chapter 4. Routing
212