Specifications

The Barracuda SSL VPN Agent

Many commonly used applications typically operate using unsecured protocols to facilitate the

exchange of data. To the casual home user this is usually not a worry, though to the corporate user this

is a critical vulnerability and one that leaves a business open to all manner of threats from password

sniffing to industrial espionage.

With modern encryption protocols like SSL, data from these applications can be “tunneled” inside SSL

packets. In the Barracuda SSL VPN appliance this is achieved through the use of the SSL VPN Agent

– a small program that can intercept data transmitted by the insecure application, encrypting said data

and transmitting the secure form over the wire. At the receiving end the appliance decrypts this data

and forwards it to the appropriate destination within the trusted network.

What is the Barracuda SSL VPN Agent?

With the Barracuda SSL VPN appliance comes a small SSL VPN Agent. This is a Java application that

works in conjunction with your user session to provide SSL tunneling and application launching

facilities provided by the appliance.

The Barracuda SSL VPN Agent is launched by a small Java applet placed on all pages that require

access to the SSL VPN client. You only need to launch the client once per user session.

The Barracuda SSL VPN Agent is an essential tool for providing a secure tunnel for some of the

resources detailed later in this chapter. When required the resources automatically starts the Agent.

However the Agent can also be started manually in which case any resource requiring the use of the

tunnel will not need to start the Agent.

Communication with Browser

The Barracuda SSL VPN Agent listens on a number of ports in the 65500+ range. This is normal

behavior. The Agent is actually also a HTTP server and uses these ports to communicate with your

Web browser. All outbound network communications are sent through the HTTPS port 443.

Precautions

It is important to remember that the SSL VPN Agent will provide a secure tunnel into your network

until it is closed or times out due to inactivity. Your users must make sure that they log-off from their

SSL VPN sessions. It is not wise to allow such a session to remain open and unattended even for a

short period of time. The SSL VPN Agent will time out any tunnel that is inactive for a configurable

period of time.