Motorola BSR 64000 Reference Manual page 285

Access List Commands
Introduction
This chapter describes the access list commands used with the BSR 64000™.
Access lists are used on the BSR to control entry or exit access to or from the BSR.
Access lists are also used within a route-map statement that is part of the routing
configuration. Access lists can be configured for all routed network protocols to filter
packets as the packets pass through the BSR. The access list criteria can be defined by
the source or the destination address, upper-layer protocol, or other routing
information.
There are many reasons to configure access lists including to restrict contents of
routing updates or to provide traffic flow control. One of the most important reasons
to configure access lists is to provide a basic level of security on the network. All
packets passing through the BSR can be allowed onto all parts of the network if an
access list is not part of the router configuration.
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