User Guide

Utilities 59
Utilities Reference
103-000153-001
August 29, 2001
Novell Confidential
Manual 99a38 July 17, 2001
The following table shows filtering support for protocols:
Table 1 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.)
Protocol Packet Forwarding Filter Service Information Filter Routing Information Filter
IPX X X X
AppleTalk X X
TCP/IP X X