Draytek Vigor 2200V, User Manual

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Firewall Setup
6-3
General Setup Some general settings of Call Filter and Data Filter are
available from this link.
Filter Setup Here are 12 filter sets for IP Filter configurations..
Dos Defense Click it to set up the DoS defense facility for detecting and
mitigating the DoS attacks.
URL Content Filter Here provides the capability of blocking inappropriate web
sites to protect child in school or at home.
The General Setup function contains, by default, two types of filter sets:
Call Filter set and Data Filter set. The Call Filter is used for users that
attempt to establish a connection from LAN side to the Internet. The Data
Filter set is used to determine what kind of IP packets is allowed to pass
through the router when the WAN connection has been established.
Conceptually, when an outgoing packet is to be routed to the WAN, the IP
Filter will decide if the packet should be forwarded to the Call Filter or Data
Filter. If the WAN link is down, the packet will enter the Call Filter. If the
packet is not allowed to trigger router dialing, it will be dropped. Otherwise,
it will initiate a call to establish the WAN connection.
If the WAN link of the router is up, the packet will pass through the Data
Filter. If the packet type is set to be blocked, it will be dropped. Otherwise,
it will be sent to the WAN interface. Alternatively, if an incoming packet
enters from the WAN interface, it will pass through the Data Filter directly.
If the packet type is set to be blocked, it will be dropped. Otherwise, it will
be sent to the internal LAN. The filter architecture is shown below.