D-Link DFL-1600 User Manual page 223

20.3. Why VPN in Firewalls
Figure 20.3: VPN Deployment Scenario 3
Internet connectivity depends on the Security Gateway
The firewall cannot inspect nor log plaintext from the VPN
VPN traffic should not normally be considered to be an integrated part of
the internal network.
On the Internal Network
(Figure 20.4)
Figure 20.4: VPN Deployment Scenario 4
Benefits
The firewall can protect the Security Gateway
Internet connectivity does not depend on the Security Gateway
Drawbacks
The firewall cannot inspect nor log plaintext from the VPN
Special routes need to be added to the firewall, or to all internal
clients participating in the VPN
Support for roaming clients is very hard to achieve
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