The Ssl Vpn Client Login - D-Link DFL-1660 User Manual

9.6.3. Installing the SSL VPN Client
Chapter 9. VPN
Figure 9.5. The SSL VPN Client Login
The difference between the two approaches above is that when the SSL VPN client software is
started by browsing to the SSL VPN interface, the correct settings for the tunnel are downloaded to
the SSL VPN client software and stored as the client's configuration file.
As long as these settings have not changed between tunnel sessions, it is possible to start the SSL
VPN client software running by selecting it in the Start menu and connecting to the same SSL VPN
interface. In particular, the SSL VPN client checks the certificate used by the SSL VPN interface by
comparing a certificate fingerprint stored in the configuration file with a fingerprint sent by the
interface.
The reason for checking the certificate in this way is that it solves the "man in the middle" problem
where a malicious third party might try to intercept communications between the firewall and the
client.
Custom Server Connection
When the SSL VPN client software is started, it is possible to connect to an SSL VPN interface on a
NetDefend Firewall that has not been connected to before. This is done by enabling the option
Specify Custom Server and explicitly specifying the IP address, port and login credentials for the
server.
With the Specify Custom Server option enabled, the SSL VPN client ignores any configuration file
parameters previously downloaded by an SSL VPN connection established using the web interface.
In particular, it does not check the certificate used by the firewall.
The disadvantage of using the custom server option is that there is no certificate checking and the
"man in the middle" problem remains.
Client Transfer Statistics
When the SSL VPN client is running, an icon for it will appear in the system tray. Clicking this icon
will bring up the client's interface showing amounts of data transferred since tunnel setup.
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