Novell NETWARE 6-DOCUMENTATION Manual page 1871

Service Information Filters
Routing Information Filters
Although packet forwarding filters provide the highest level of security, they
might affect the performance of the router because the filters are applied to
each data packet received by the router.
Packet forwarding filters are available for IPX and TCP/IP protocols.
Service information filters restrict the advertisement or acceptance of
specified services by filtering out information in the data packets that
advertise the services destined for particular parts of the network. These filters
increase security by limiting the visibility of selected services. However,
service information filters provide a lower level of network security than
packet forwarding filters because they only monitor service information
packets. They also reduce the network traffic caused by periodic service
information messages sent by routers.
Service information filters are available for IPX (as outgoing and incoming
SAP filters) and AppleTalk (as device hiding filters).
Routing information filters restrict the exchange of routing information
between routers by limiting the routes added to the routing tables of specified
routers. These filters increase network security by limiting the visibility of
specified networks. However, like service information filters, routing
information filters provide a low level of network security because they only
monitor routing information packets. They also reduce the network traffic
caused by the periodic exchange of routing information messages between
routers.
Routing information filters are available for IPX, AppleTalk, and TCP/IP.
There are two types of routing information filters:
Outgoing routing information filters, which limit the route
advertisements sent out by a router to a specified set of routers
Incoming routing information filters, which limit the acceptance of route
advertisements received by the router from its neighboring routers
For more information about routing information filters, refer to
"Outgoing Routing Information Filters" on page 12
"Incoming Routing Information Filters" on page 13
11
Understanding