Purpose

Use at the server console to set up and configure filters for IPX, TCP/IP, and AppleTalk protocols.

Syntax

LOAD FILTCFG

Filters help you control what kind of information is sent and received by a router by selectively discarding packets of specified types.

Filters help you to limit specific kinds of traffic to a certain part of your network, or to provide security.

NetWare 4.11 provides the following filter types:

• Packet forwarding
• Service information
• Routing information

The following table shows filtering support for protocols:

Table 2. Filtering Support for Protocols

Packet Forwarding Filters

Packet forwarding filters restrict access to services by filtering data packets sent by the restricted location to the service location.

Because these filters don't restrict Service Advertising Protocol (SAP) packets sent by servers, restricted users might see advertisements of services even when they cannot access the service.

Although these filters provide the highest level of security of all the filters, they might affect the performance of the router because the filters are applied to each data packet the router receives.

Service Information Filters

Service information filters restrict service advertisement on a router's internetwork.

This type of filtering provides low-level security by preventing users from finding the network addresses of services.

It also reduces the network bandwidth consumed by periodic service broadcasts.

Service information filters are of two types:

• Service advertisement filters limit the service advertisements sent by a router for a specified set of services to a specified set of networks.
• Service acceptance filters limit the acceptance of service advertisements received by the router for a specified set of services at a specified set of networks. (By filtering what a router sees, you are restricting the set of services that are advertised by the router on any other interface.)

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. They also reduce the bandwidth used by the periodic exchange of routing information between routers.

Routing information filters are of two types:

• Route advertisement
• Route acceptance

When you add a routing information filter, an implicit server filter is also added for all services residing on the filtered networks.