Novell NETWARE 6-DOCUMENTATION Manual page 1872

Outgoing Routing Information Filters
12
Filter Configuration
Outgoing routing information filters limit routing information advertised by a
router to its neighboring routers. When these filters are enabled on a router,
only the allowed routes are advertised to each neighboring router. This hides
specified routes from some routers and from certain parts of the network.
A typical outgoing routing information filter consists of the route to the
destination network and the interface through which filtered advertisements of
the route are sent. The filters affect all routers on the network to which this
interface connects.
Outgoing routing information filters might not affect whether the end stations
that are on the same LAN segment as the filtering router can access the filtered
routes. Because these filters only keep from advertising filtered routes to other
routers but do not affect the filtering router's routing table, the filtering router
delivers all packets that it receives as destined for filtered routes.
End stations at least one router away usually cannot access networks with
routes that are filtered out.
In addition to being able to filter by interface, you can also filter on a WAN
circuit. You can assign filters with specific circuit information, including
remote system ID, remote DTE address, and DLCI number. If the specific
router is connected by the specified circuit information in the filter, then the
filter is applied. Filtering on circuits is supported for X.25, ATM, frame relay,
and PPP.
Figure 1 on page 13
filtered.
shows two networks; the route for one network has been