Kerio Tech Firewall6 - Manual (Page 98)

Chapter 7 Traffic Policy
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Figure 7.37 Service definition without inspector protocol
Figure 7.38 This traffic rule allows accessing service without protocol inspection
Warning
To disable a protocol inspector, it is not sufficient to define a service that would not use the
inspector! Protocol inspectors are applied to all traffic performed by corresponding protocols
by default. To disable a protocol inspector, special traffic rules must be defined.
7.8 Use of Full cone NAT
However, many applications (especially applications working with multimedia, Voice over IP
technologies, etc.) use another traffic method where other clients can (with direct connection
established) connect to a port “opened” by an outgoing packet. For these cases, WinRoute
includes a special mode of address translation, known as Full cone NAT. In this mode, opened
port can be accessed from any IP address and the traffic is always redirected to a correspond-
ing client in the local network.
Use of Full cone NAT may bring certain security risk. Each connection established in this mode
opens a possible passage from the Internet to the local network. To keep the security as high
as possible, it is therefore necessary to enable Full cone NAT for particular clients and services
only. The following example refers to an IP telephone with the SIP protocol.
Note: For details on traffic rules definition, refer to chapter 7.3 .